Download Pathfinder Radar/Chartplotter Series Service Manual

Pathfinder Radar/Chartplotter Series
Pathfinder Radar/Chartplotter Series
Service Manual
GAIN
DISPLAY
VRM/EBL
MARKS
MULTI
ENTER
POWER
CLEAR
Part 2
Preface
RANGE
ALARMS
MENU
D3851-1
Part 2 - Radome Scanner Units
Document No: 83139
Warning
CE Marking of Equipment/Replacement Parts
If the Raytheon/Autohelm equipment under repair, test, calibration, installation or setting to work carries the European CE
mark, only parts and components supplied or approved for such use by Raytheon should be used in order to maintain
compliance with the relevant CE requirements.
Incorporation, use or attachment, by any means, of parts or components not supplied for or not approved for such use by
Raytheon or, if supplied or approved for use by Raytheon, not properly fitted in accordance with instructions published,
provided or recommended by Raytheon, may cause the equipment to malfunction and, in particular, to become unsafe or
to no longer meet the relevant CE requirements. In these circumstances, Raytheon Marine Company excludes liability to
the fullest extent permissible in law for any loss or damage including any liability for its contribution to such loss or damage
by its negligent acts or omissions .
Service Manual 83139-1-PR i
Pathfinder Radar/Chartplotter Series
Safety Notices
This radar/chartplotter equipment must be installed and operated in
accordance with the instructions contained in the Owner's Handbook.
Failure to do so can result in personal injury and/or navigational
inaccuracies. In particular:
1. High Voltage
Part 2
Preface
The radar scanner unit contains high voltages. The radar should always be
turned off before removing the covers. The scanner unit high voltage can
take up to 1 minute to decay. The specialised service procedures should only
be carried out by qualified service technicians.
2. Electromagnetic Energy
The radar scanner transmits electromagnetic energy. It is important that the
radar is turned off whenever personnel are required to come close to the
scanner to perform work on the scanner assembly or associated equipment.
DANGER
Non-ionising Radiation
It is recommended that the radar scanner is mounted out of range of
personnel (above head height).
Avoid looking directly at the antenna as your eyes are the most sensitive part
of the body to electromagnetic energy.
When properly installed and operated, the use of this radar will conform to
the requirements of ANSI / IEEE C95.1-1992 Standard for Safety Levels
with Respect to Human Exposure to Radio Frequency Electromagnetic
Fields, 3Hz to 300 GHz.
3. Magnetron
Persons with cardiac pacemakers must not engage in service or
preventative maintenance of the radar, in close proximity to the magnetron.
There is danger of abnormal operation of cardiac pacemakers.
4. Navigation Aid
This radar unit is only an aid to navigation. Its accuracy can be affected by
many factors, including equipment failure or defects, environmental
conditions, and improper handling or use. It is the user’s responsibility to
exercise common prudence and navigational judgements. This radar unit
should not be relied upon as a substitute for such prudence and judgement.
Warranty
When a repair is carried out by an authorised Raytheon service
representative, some or all of the cost may be covered by the Raytheon
warranty. Refer to the Limited Warranty Certificate reproduced for guidance
at the beginning of Part 1.
ii Service Manual 83139-1-PR
Contents
Contents
Chapter 2. Technical Description .......................................................................................... 3
2.1 Overview ......................................................................................................... 3
Scanner configuration .................................................................................... 3
Receiver configuration (LNC/IF) ...................................................................... 4
Low Noise Converter/Limiter (LNC) ................................................................. 4
2.2 Modulator / PSU – Interface Description............................................................. 6
Connectors .................................................................................. 6
Ship Supply Power Input (CN1) ...................................................... 6
PSU Control/Status (CN2) ............................................................. 6
Modulator Control/Status (CN2) ..................................................... 6
Motor Control................................................................................ 7
Ships Heading Interface ................................................................ 7
Receiver Power Supply ................................................................. 7
Stepper Motor Interface ................................................................. 7
Ships Heading Sensor Opto-coupler Interface ................................. 7
Magnetron Interface ...................................................................... 8
2.3 Modulator / PSU – Circuit Description ................................................................ 8
Design Overview ........................................................................................... 8
Circuit Description .......................................................................................... 9
EMC Filter............................................................................................. 9
Over Voltage Protection ......................................................................... 9
Supply Reversal Protection .................................................................... 9
DC-DC1 and Start / Shutdown Circuit ..................................................... 9
Scanner operating supply voltage range ......................................... 9
Output Specification DC-DC1 ...................................................... 10
DC-DC2 ............................................................................................. 10
Output Specification DC-DC2 ...................................................... 10
Modulator ........................................................................................... 11
Modulator Clock, PRI_PLS .................................................................. 12
Ships Heading Sensor ......................................................................... 12
Stepper Motor Controller ...................................................................... 12
2.4 IF Receiver PCB – Interface Description .......................................................... 12
Connectors ................................................................................ 12
Display Connector (SK1) ............................................................. 13
LNC Connector (P1).................................................................... 14
Mod / IF Interconnect (P4)............................................................ 14
Service Manual 83139-1-TC iii
Part 2
Preface
Chapter 1. Introduction ......................................................................................................... 1
Pathfinder Radar/Chartplotter Series
Part 2
Preface
2.5 IF Receiver – Circuit Description ...................................................................... 14
Main Receiver ..................................................................................... 14
Summary of bandwidths, pulse widths and PRI rates ..................... 15
Autotune Receiver ............................................................................... 15
STC/Main Bang Suppression (MBS) ..................................................... 15
Microcontroller .................................................................................... 16
Initial Scanner set up (EEprom stored values) ........................................ 16
2.6 Antenna / Rotary Joint Assembly ..................................................................... 17
2.7 Scanner Display Connection ........................................................................... 18
Chapter 3. Fault Finding ...................................................................................................... 19
3.1 Safety Notices ............................................................................................... 19
3.2 General Notes ............................................................................................... 19
3.3 Built-in Testing / Diagnostics ............................................................................ 20
3.4 Master and Repeater LCD Displays ................................................................. 20
3.5 Check Lists .................................................................................................... 21
Check List 2 ................................................................................................. 21
Scanner Not Responding message displayed or Start-up countdown restarts
unexpectedly ............................................................................................... 21
External Checks .................................................................................. 21
Display Circuit Operation ...................................................................... 22
Display Internal Checks ....................................................................... 22
Display Check 1 - Display has no power at scanner plug at rear of
display ....................................................................................... 22
Display Check 2 - Display communications check .......................... 23
Display Check 3 - Display countdown restarts unexpectedly ........... 23
Scanner Internal Checks ...................................................................... 23
Scanner Check 1 - scanner communications checklist ................... 23
Scanner Check 2 - scanner power checklist .................................. 23
Check List 3 ................................................................................................. 24
Radar Target Image blank / faulty (missing radar targets, no radar scan, poor
performance, etc.) ........................................................................................ 24
External Checks .......................................................................................... 24
Check List 9 ................................................................................................. 34
MOD/PSU PCB ........................................................................................... 34
General Information ............................................................................. 34
Magnetron Dummy Load ..................................................................... 34
Ship Supply Power Input ...................................................................... 35
Receiver Power Supply Output ............................................................. 35
Magnetron Interface ............................................................................ 36
Ships Heading Sensor Opto-coupler Interface ....................................... 36
iv Service Manual 83139-1-TC
Contents
Chapter 4. Setting-up Procedures ...................................................................................... 45
4.1 Fitting of Replacement IF Receiver PCB .......................................................... 45
4.2 Fitting of Replacement Magnetron or LNC ....................................................... 45
4.3 Bearing Alignment ......................................................................................... 45
4.4 Display Timing ............................................................................................... 45
4.5 Tune Preset ................................................................................................... 46
Chapter 5 . Replacement Parts ........................................................................................... 47
5.1 Spare Parts Lists ............................................................................................ 47
18'' Radar Scanner Unit ................................................................................ 47
24'' Radar Scanner Unit ................................................................................ 47
Radar Core Assembly .................................................................................. 48
18" and 24'' Scanner (common spares) ......................................................... 49
4.2 18'' and 24'' Scanner Units - replacement of parts ............................................ 49
Category A ................................................................................. 50
Category B ................................................................................. 51
Chapter 6. Drawings ........................................................................................................... 55
List of drawings.................................................................................................... 55
18" (2kW) and 24" (4kW) Scanner Interconnections ....................................... 56
Modulator/PSU Board – Top level .................................................................. 57
Modulator/PSU Board – Low Voltage PSU ..................................................... 58
Modulator/PSU Board – High Voltage PSU .................................................... 59
Modulator/PSU Board – Modulator ................................................................ 60
Modulator/PSU Board - 3 Phase DC brushless motor drive ............................. 61
Modulator/PSU Board – Stepper Motor Drive ................................................. 62
Modulator/PSU Board – PCB layout (2kW, stepper motor) .............................. 63
Modulator/PSU Board – PCB layout (4kW, stepper motor) .............................. 64
IF Receiver – Top level ................................................................................. 65
IF Receiver – PCB Layout ............................................................................. 66
Service Manual 83139-1-TC v
Part 2
Preface
Ships Heading Output ......................................................................... 36
Stepper Motor Control ......................................................................... 36
Stepper Motor Interface ....................................................................... 37
PSU Control/Status ............................................................................. 37
Modulator Control/Status ..................................................................... 38
3.6 Diagnostics Menu – detailed description .......................................................... 39
Part 2
Preface
Pathfinder Radar/Chartplotter Series
vi Service Manual 83139-1-TC
Chapter 1. Introduction
Chapter 1. Introduction
This Raytheon Service Manual contains information to assist with maintenance and service. It is
intended to be used by qualified Raytheon service representatives.
The contents of this manual, as a whole, relate to the Raytheon ‘Pathfinder‘ radar series and the
associated chartplotter displays. The manual is divided into several parts. This part relates to the
two radome scanner units:
• 2D 18" radome, 2 kW scanner unit
Other parts relate to General matters and (small groups of) specific units. Refer to the Master Table
of Contents at the front of the manual for brief details of each of the other parts. Further parts will be
added to the manual as this family of products grows.
Overview
Chapter 2: Contains the technical description of the radome scanner units and gives a general
overview of the complete unit, then brief details of each PCB or main circuit.
Chapter 3: Part 1, Chapter 3 provides information to isolate radar problems to either a scanner or a
display unit. This Chapter then gives further fault finding procedures, specifically for the radome
scanner units, utilising the built-in diagnostics, flow charts and monitoring points to reduce the
problem to PCB or sub-unit level.
Chapter 4: Contains any setting-up that may be necessary after service or fitting of a spare part.
Chapter 5: Contains the spare parts lists that are cross-referenced to the exploded view drawings
to aid identification. These drawings are also used for dismantling and assembly. Additional notes
supplement the drawings.
Chapter 6: Contains the scanner unit interconnection drawing, circuit diagrams and their
associated layouts.
Service Manual 83139-1-Ch1 1
Part 2
Chapter 1
• 4D 24" radome, 4 kW scanner unit
Part 2
Chapter 1
Pathfinder Radar/Chartplotter Series
2 Service Manual 83139-1-Ch1
Chapter 2. Technical Description
Chapter 2. Technical Description
2.1 Overview
Scanner configuration
Antenna/Rotary joint assembly
Motor
2/4kW
Part 2
Chapter 2
Transition
60dBm (maximum)
W/Guide
limiter
Magnetron
Low Noise
Converter
Circulator
-20dB (nominal)
Modulator, PSU board
IF Receiver, micro, I/O board
Ships power
Scanner uplink connection
D4054-1
Figure 1. Scanner Block Diagram
The system comprises the functional blocks as shown in the above diagram. The basis of operation
is as follows:
The Modulator, PSU board generates a high voltage pulse of 80nS, 250nS or 700nS duration
dependant upon the range setting and the corresponding IF/Video filter control lines. This pulse
begins on the rising edge of a negative going trigger at a pulse repetition frequency (PRF) also
defined by the range setting. The resulting pulse is output to the magnetron which converts the
energy into an RF pulse at a frequency of 9.41GHz (nominal).
All supply requirements are also provided by the Modulator, PSU board.
The RF pulse is routed to an antenna via a 3-port circulator which propagates microwave energy
in only one direction and thereby provides isolation between the transmit source and the low noise
converter. A rotary joint is used to maintain continuity between a waveguide output from the
circulator and a microstrip input to the antenna. This is achieved via transitions into, and back out of,
a section of co-axial line which is configured with a ‘split’ perpendicular to the axis of rotation. The
energy is then radiated by the antenna with a narrow azimuth beam shape (5.2° for the 18" patch,
3.9° for the 24" patch), with low sidelobe levels (<-22dB). The elevation beamwidth is maintained at
approximately 25° in order to illuminate targets during pitch and roll of the transmitting vessel.
Echoes are returned due to reflections from potential targets such as boats, buoys, land etc, and in
the form of clutter from sea, rain, etc.
The returned energy is collected by the same antenna used to transmit the original pulse and is
routed through the circulator to the low noise converter (LNC). These comparatively low level
signals are amplified by a low noise transistor in order to maintain signal/noise performance and are
mixed down to an IF frequency of 60MHz nominal for further amplification and subsequent
detection.
Service Manual 83139-1-Ch2 3
Pathfinder Radar/Chartplotter Series
The IF receiver board provides further low noise amplification and adjustable gain to maximise the
dynamic range (“dynamic attenuation control”) in the presence of clutter, target and range variations.
The IF board also includes a logarithmic detection stage with approximately 50dB dynamic range,
which provides a compressed signal output in terms of dB input power versus output Voltage level.
Various filtering stages are also employed in the IF Receiver to provide optimum signal/noise
characteristics for the detected pulse and to provide some immunity against the bulk effects of rain.
The IF Receiver also provides the interface for the up-link commands to the scanner, including
clutter and gain selection, stepper motor control and display synchronisation pulse generation.
Part 2
Chapter 2
Receiver configuration (LNC/IF)
The basic configuration of the microwave and IF receiver circuitry is as follows :
Low Noise Converter (LNC)
Limiter
IF Receiver Board
Filter select logic
Switched
Filter
LNA
Logarithmic
Detector
Video
Filter
90
HYB
Lineariser
90 deg
Lineariser
Curve Splitter
Autotune
Receiver
LNC Supplies
MBS / STC / Rain / Sea / Gain
Generation and Summing Network
Scanner uplink
D4055-1
Figure 2. Receiver Configuration (LNC/IF)
Low Noise Converter/Limiter (LNC)
The primary function of the LNC is to provide low noise amplification of the low level signal returns
and mixing to an IF frequency of 60MHz nominal.
The low noise amplification is provided by a single low noise FET, with bias conditions, and
associated matching set to minimise noise figure and maximise gain and compression levels.
Maximum gain is required so as to minimise the noise figure contribution from subsequent stages.
The mixing function is carried out in an image reject mixer configuration which reduces image noise
by 20dB nominal in order to minimise the degradation in overall noise figure.
Protection is provided in the form of three limiter diodes which are configured to become forward
biased in the presence of increasing RF power.
NOTE.There are no user / dealer serviceable parts within the LNC due to its high frequency
of operation.
4 Service Manual 83139-1-Ch2
Chapter 2. Technical Description
Tune_V
Mixer
µW I/P
60MHZIF
Limiter
LNA
90
HYB
90
degrees
+5Volts
Constant current bias circuitry
-5Volts
VCO tune compensation
Ground
D4056-1
Part 2
Chapter 2
Figure 3. LNC Configuration
P7
LNC
P1
P4
SK1
IF Receiver
Stepper
Motor
CN5
CN1
CN2
CN4
High
voltage
CN6
Magnetron
Mod/PSU/Motor
Circulator
D4057-1
Figure 4. Scanner Interfaces
Service Manual 83139-1-Ch2 5
Pathfinder Radar/Chartplotter Series
2.2 Modulator / PSU – Interface Description
The interfaces to the Mod/PSU are shown in Figure 4. and the individual signal functions are
described below :-
Part 2
Chapter 2
Connectors
Connector
Function
Type
CN1
Ships Supply connector
4 way WAGO clamp
CN2
Mod-IF interconnect
18 way Picoflex ribbon connector
CN4
Stepper motor connector
6 way Molex type
CN5
Ships heading sensor
3 way Molex type
CN6
Magnetron heater connector
2 way Molex type
Ship Supply Power Input (CN1)
Ref.
Signal Name
Type
State
Function
CN1-5
CN1-6
+BATT_IN
Power input
–
Ships power i/p
CN1-1
CN1-2
–BATT_IN
Power input
–
Ships power return
PSU Control/Status (CN2)
Ref.
Signal Name
Type
State
Function
CN2-12
Heater_EN_N
Logic input
0
1
Enable MOD + 6.3V, MOD + 300V,
MOD +12V outputs i.e. enable magnetron
heater, modulator PSU and stepper
motor PSU.
Disable the above
Modulator Control/Status (CN2)
Ref.
Signal Name
Type
State
Function
CN2-18
RADAR_TX_EN
Logic input
1
0
Enable modulator (magnetron) pulses
Disable modulator, regardless of activity on PRI_PLS
CN2-9
CN2-11
PW0,
PW1
Logic input
Logic input
PW0
0
1
0
1
CN2-8
PRI_PLS
Logic input
clock
10us+/-0.5us low. Rising edge triggers modulator
pulse. Frequency will be varied according to pulse
width; 80ns PRF = 2250Hz ; 200ns PRF=1500Hz,
700ns PRF=750Hz. See Figure 5.
CN2-3
HEATER_OK
Logic output
1
Implies magnetron heater is connected and drawing
> minimum current.
Magnetron heater faulty or magnetron disconnected.
0
PW1
0
0
1
1
Select modulator pulse width as follows :80ns pulse
250ns pulse
700ns pulse
700ns pulse (not used)
CN2-17
MOD_ISENSE
Analogue output
0-5.0V
Indicates peak magnitude of magnetron anode current
and thus indicates approximately peak R.F. power
output. See Figure 7.
CN2-16
MOD_SENSE1
Analogue output
0-5.0V
Analogue voltage indicates build standard.
CN2-13
MOD_SENSE2
Analogue output
0-5.0V
Analogue voltage indicates build standard.
6 Service Manual 83139-1-Ch2
Chapter 2. Technical Description
1/Frequency
10us +
_ 0.5us
3-5V
PRI_PLS
0-0.5V
D4059-1
Figure 5. Modulator clock format, PRI_PLS
Ref.
Signal Name
Type
State
Function
CN2-12
MOTOR_EN_N
Logic input
0
1
Enable Motor (either Stepper or 3-phase)
Disable Motor
CN2-10
STEP_IO
Logic input/output
clock
For stepper motor build standard: input at 181 Hz; 50%
duty cycle. Determines stepper motor speed.
For all build standards this line acts to identify the type
of build standard in conjunction with the
MOTOR_EN_N control as follows:
When MOTOR_EN_N=1 (motor = off) :
STEP_IO = 1 for stepper motor build standard.
Ships Heading Interface
Ref.
Signal Name
Type
State
Function
CN2-15
SHP_IN
Logic output
clock
Neg. going edge: Indicates antenna position is at
nominal zero azimuth.
Receiver Power Supply
Ref.
Signal Name
Type
State
Function
CN2-1
IF-5V
Power
–
-5V power rail to receiver
CN2-2
IF+5V
Power
–
+5V power rail to receiver
CN2-4
IF+26V
Power
–
+26V power rail to receiver
CN2-6
IF+12V
Power
–
+12V power rail to receiver
CN2-5
CN2-7
GND
GND
Power
–
Isolated GND return from receiver power rails
Stepper Motor Interface
Ref.
Signal Name
Type
State
Function
CN4-6
STMO1
Analogue
–
Phase A2 switch
CN4-5
STMO2
Power
–
+12Vmotor
CN4-4
STMO3
Analogue
–
Phase A1 switch
CN4-3
STMO4
Analogue
–
Phase B1 switch
CN4-2
STMO5
Power
–
+12Vmotor
CN4-1
STMO6
Analogue
–
Phase B2 switch
Ships Heading Sensor Opto-coupler Interface
Ref.
Signal Name
Type
State
Function
CN5-1
BZ
Analogue
–
Opto emitter connection
CN5-2
+5V
Power
–
+5V to Opto LED anode and collector connection
CN5-3
SHGND
Power
–
Current limited Opto LED cathode GND connection
Service Manual 83139-1-Ch2 7
Part 2
Chapter 2
Motor Control
Pathfinder Radar/Chartplotter Series
Magnetron Interface
Ref.
Signal Name
Type
State
Function
CN6-1
HEATER
Analogue output
–
Magnetron heater/cathode power and signal
connection.
CN6-2
HEAT/CATH
Analogue output
–
Magnetron heater/cathode power and signal
connection.
Note: The polarity of these two signals is immaterial. The magnetron anode connection is made
through the body of the device to the local GND.
Part 2
Chapter 2
2.3 Modulator / PSU – Circuit Description
Design Overview
The Modulator / PSU PCB integrates the modulator, power supply and motor drive functions of the
radar scanner assembly.
The power supply section provides regulated power to all functions within the scanner unit. The
modulator drives the magnetron when triggered from a simple logic input with one of three pre-set
pulse widths selected by the IF receiver. The Motor Controller drives the stepper motor which
rotates the antenna.
One common PCB design is used for all current Pathfinder radar systems, however the build
standard is changed to suit differing configurations (motor type, magnetron power, etc).
The figure below shows an overall block diagram of the Mod/PSU PCB showing the principal circuit
blocks :
Stepper Motor Drive
MOTOR_EN_N
Mod +6V3
Mod +300V
sync. clock
Stepper Motor (option)
Mod +12V
DC-DC2
Modulator
PSU
Modulator
Magnetron
Vx
DC-DC1
Receiver
PSU
PRI_PLS
PW0
PW1
STEP_ I0
RADAR_TX_EN
MOD_ISENSE
IF+5V
IF--5V
IF+12V
IF+26V
HEATER_EN_N
SHP_IN
control
Vx
Startup / Shutdown Cct
Ship's Heading Interface
Supply Reversal
Protection
EMC Filter
Ships Heading
Sensor
Ship's
Supply
Higate
Figure 6. Modulator/PSU Overview
8 Service Manual 83139-1-Ch2
IF Receiver
Over Voltage
Protection
CN1 - Ship Supply
CN2 - Mod-IF Interconnect
CN4 - Stepper Motor
CN5 - Ships Heading
CN6 - Magnetron
Vx is internal 11.5V supply rail (primary side ref.)
HiGate is internal supply rail (primary side ref.)
D4058-2
Chapter 2. Technical Description
Circuit Description
EMC Filter
The EMC filter section comprises of a common mode inductor and associated filter capacitance’s to
minimise EMC problems with other electronic equipment.
Over Voltage Protection
A varistor, VD1, protects the unit from over voltage surges.
The scanner is protected from inadvertent reversal of the ships supply by FET, Q56. This FET will
not connect the ships supply to the board as long as its polarity is reversed. When the ships supply is
connected correctly the FET will switch on as the internal charge pump formed by D59, D60, etc
drives the HIGATE supply to approx. 12V greater then the ships supply voltage.
DC-DC1 and Start / Shutdown Circuit
This is a switch mode power supply unit which derives the low voltage supplies for the receiver
assembly. It is configured as a flyback converter whereby the ships supply is switched at approx.
72kHz across the primary of transformer Tx2 by FET Q38. Pulse width modulation (PWM) control is
by IC U12 which senses the voltage of an internal power rail, Vx, and drives the FET to maintain
voltage regulation. With the exception of the internal supply Vx which has the ships supply as its
ground reference, all other output voltage rails are isolated from the ships supply and therefore must
be ground referenced to the secondary side when measured (note when fitted within the core
assembly the secondary side ground reference is connected to the main metal casting).
This supply is itself powered from one of its own output rails, Vx ,the power back winding with initial
start-up current from the ships supply. The supply is protected from operation at inadequate ships
supply voltages by the start/shutdown circuit comprising of Q57, Q58, etc. This circuit will shut the
supply down if the ships supply falls below the minimum scanner operating voltage of 8.7V.
This supply is configured as the ‘master’ supply and therefore it must be running before the high voltage
supply DC-DC2 will function.Thus a fault in this unit is likely to shutdown the high voltage supply.
Scanner operating supply voltage range
Parameter
Units
Min.
Max.
Conditions
Input Voltage Range
V
8.7
32.0
Measured at PCB input terminals.
Reverse polarity leakage current
uA
0
+/-100
Continuous ignoring any initial transient.
Max. Leakage current between
isolated secondary GND and ships
-BATT_IN (CN1-1/4)
uA
0
+/-1
Measured with 32.0V differential imposed between BATT_IN and isolated GND.
Service Manual 83139-1-Ch2 9
Part 2
Chapter 2
Supply Reversal Protection
Pathfinder Radar/Chartplotter Series
Part 2
Chapter 2
Output Specification DC-DC1
Parameter
Units
Min.
Nom.
Max.
IF-5V output voltage
V
-5.6
-6.0
-6.4
IF-5V load
mA
0
IF+5V output voltage
V
4.7
IF+-5V load
mA
50
IF+12V output voltage
V
11.2
IF+12V load
mA
0
IF+26V output voltage
V
25.0
IF+26V load
mA
1
125
5.0
Load will be reduced to minimum during
standby state of IF receiver.
12.4
300
27.0
Load will be reduced to minimum during
standby state of IF receiver.
5.3
350
12.0
Conditions
Load will be reduced to minimum during
standby state of IF receiver.
29.0
2
DC-DC2
The operation of this switch mode power supply is very similar to DC-DC1. This supply generates
the magnetron heater supply, the modulator high voltage supply (200-300V) and the 12V supply for
the stepper motor. As for DC-DC1 a PWM control IC, U11, regulates the switching of a FET, Q37,
which switches the ships supply across the primary of transformer Tx1. U26 and associated
components, provide voltage feedback from the magnetron heater voltage rail. The high voltage
modulator supply rail comprises of a number of series connected secondaries.
The PWM controller switches in synchronisation with DC-DC1 at approximately 72kHz. This supply
is a slave to DC-DC1 and will shutdown with DC-DC1.
This supply is switched on by a low state on the the control signal, HEATER_EN_N (CN2-12). In
normal operation this supply is disabled only when the radar is switched to ‘standby mode’.
Note: This supply requires that a magnetron heater load (or a 12 ohm/4W resistor) is connected at
CN6 in order to function correctly, if the supply is operated with no connection at CN6 no damage
will occur but the supply voltages may be found to be out of specification. (Also see Stepper Motor
Controller)
Output Specification DC-DC2
Parameter
Units
Min.
Nom.
Max.
Conditions
MOD+6.3V output voltage
V
6.0
6.3
6.6
Measured as differential voltage at CN6
MOD+6.3V load
mA
430
MOD+300V output voltage
V
196
MOD+300V load
mA
0
MOD+300V output voltage
V
250
MOD+300V load
mA
0
MOD+12V output voltage
V
11.2
MOD+12V load
mA
350
10 Service Manual 83139-1-Ch2
650
210
270
12.0
224
2kW systems
25
2kW systems
288
4kW systems
50
4kW systems
12.8
500
2-phase, unipolar stepper motor
Chapter 2. Technical Description
Modulator
IMPORTANT: The modulator circuit contains very high voltages and energy levels, care
should be exercised in all maintenance activities in this area. Only those items which appear
on the RME spares list may be replaced.
The modulator comprises a high voltage pulse transformer, Tx3 and a switching FET Q42 together
with associated control and pulse shaping circuitry. In operation the control circuitry selects one of
three pulse widths which then drive the FET gate via IC U22. As the FET turns on it switches the
high voltage supply, +MOD_300V, across the very low impedance of the pulse transformer primary.
The current rapidly rises in the FET and its series source resistors (R132, R133, etc) until the FET
begins to turn-off thus holding the current at a constant level. The resulting primary voltage pulse
causes an associated secondary pulse stepped-up by the transformer turns ratio to several kV.
When the secondary voltage reaches the magnetron switch-on threshold it will ‘fire’ generating a
burst of microwave power at several kW and at a frequency of approx. 9.4GHz.
The FET is protected from operation at excess temperature by a thermistor, PT1 screwed to the
FET heatsink and its associated circuitry. It is further protected from operation with unstable supply
voltage by Q54.
The control circuitry comprises of a number of monostables. Each of which generates one of the
three different pulse widths used for different range settings. Three variable resistors, RV1, RV2 and
RV3, set the exact pulse width required. These variable resistors are preset at the factory. They
require specialist equipment for tuning and must not be adjusted by the service engineer.
Two circuit blocks monitor the performance of the modulator / magnetron to provide diagnostic
information for service personnel which may be read in the diagnostics menu at the display unit.
•
Comparitor Q62, Q63 senses the correct flow of magnetron heater current and provides
anoutput,HEATER_OK which is normally a logic high when the magnetron is connected and the
high voltage supply is enabled (in transmit mode or during the 70 second warm-up period).
•
Peak detector D55, etc detects the peak pulsed magnetron current flow and derives the signal
MOD_ISENSE which gives some indication of the transmit power. Note that the presence of the
pulse shaping circuitry alone results in some current flow and so this indicator must be
interpreted with care.
System
Power
Parameter
Units
80ns Pulse Width
250ns Pulse Width
700ns Pulse Width
Min.
Max.
Min.
Max.
Min.
Max.
2kW
MOD_ISENSE
V
1.9
3.0
2.2
3.0
2.2
3.0
4kW
MOD_ISENSE
V
1.3
2.4
1.6
2.4
1.8
2.4
Conditions
Figure 7. MOD_ISENSE Voltage
Service Manual 83139-1-Ch2 11
Part 2
Chapter 2
The modulator’s function is to drive the magnetron in order to generate a transmit pulse at approx.
9.4GHz to the antenna. The modulator is required to generate three different pulse widths as
selected by external logic control lines, PW0, PW1. The modulator is fired when triggered by the
rising edge of the PRI_PLS logic level control signal from the micro controller. In addition a further
control line RADAR_TX_EN is used to over-ride PRI_PLS and disable transmission when held low.
Output sense lines indicate correct operation to the external micro controller.
Pathfinder Radar/Chartplotter Series
Modulator Clock, PRI_PLS
1/P.R. Frequency
10us +
_ 0.5us
3-5V
PRI_PLS
0-0.5V
Figure 8. Modulator clock, PRI_PLS
Part 2
Chapter 2
Ships Heading Sensor
The ships heading sensor is used to indicate that the antenna is aligned with the vessels fore and aft
line. It provides one output pulse per antenna revolution. This information is utilised by the IF receiver
to synchronise the radar output to the ships heading.
A slotted optical transducer is interrupted by the principal gear of the antenna rotary joint assembly.
This results in a negative going pulse at CN5-1. This pulse is variable in amplitude with ambient
lighting level and device tolerance. This pulse is conditioned by the interface formed by U23 and
reappears as SHP_IN at CN2-15 as a negative going pulse of approximately 5V amplitude. If the
antenna is rotating normally this pulse will have a repetition rate of approximately 2.5 seconds.
Stepper Motor Controller
A stepper motor is used to rotate the antenna of all radome radar units. The stepper motor is a
2-phase unipolar type driving the antenna main gear by means of a flexible belt. The stepper motor
is mounted to the main casting which provides heat sinking for the motor. The motor frequency is
determined by the frequency of the external drive clock, STEP_IO which originates at the IF board
micro controller and is nominally 181Hz. The motor drive interface comprises U24 and associated
circuitry. An enable signal, MOTOR_EN_N switches the motor drive on when at logic 0. The motor is
connected at CN4. Pins 2 and 5 are the raw 12V motor supply (only active when the high voltage
PSU, DC-DC2, is enabled). Pins 1,3,4 and 6 carry the motor winding drive signals. If any winding
drive signal becomes disconnected the motor will normally fail to rotate but will vibrate instead. If the
magnetron heater at CN6 is disconnected the motor may rotate with reduced torque.
2.4 IF Receiver PCB – Interface Description
The Interfaces to the IF Receiver are shown in Figure 4.
The individual signal functions are described below:-
Connectors
Connector
Function
Type
SK1
Display connector for serial
communications video and
syncronisation timing signals
8 way Molex C-grid socket
P1
LNC connector
20 way SAMTEC CLH-110-F-D-DV-P
(7 pins used only)
P4
Mod-IF interconnect
18 way Picoflex ribbon connector
12 Service Manual 83139-1-Ch2
Chapter 2. Technical Description
Ref.
Signal Name
Type
State
Function
SK1-1
SK1-2
AZ_SHP_OUTB
AZ_SHP_OUT
clock, differential pair
output
normally high, low going clock
normally low, high going clock
0 - 5.0V
A differential output pair providing
azimuth pulses to synchronise antenna
position with the display (10us duration
at approximately 820 Hz). The SHP
(ships heading position) pulse is
superimposed on the signal once per
antenna revolution (30us pulse every
2.5 secs)
SK1-3
SK1-4
SER_IOB
SER_IO
digital comms,
differential pair
bi-directional
2.2 V nom. DC bias
2.8 V nom. DC bias
An RS485 Bi-directional serial
communications link operating at 19.2
kBaud. It provides control of the
scanner operation and monitoring
functions from the Radar display.
SK1-5
SK1-6
PRI_OUTB
PRI_OUT
clock, differential pair
output
normally low, high going clock
normally high, low going clock
0 - 5.0V
A differential output pair providing PRI
(Pulse Repetition Interval) pulses to
synchronise the firing of the transmitter
with the display video. Rate is according
to range setting.
SK1-7
SK1-8
VIDEO GND
VIDEO
Analogue Video
output
AC coupled 1.75V max peak
signal into 75 ohms
The raw Radar video signal from the
scanner.
10us +
_ 0.5us
approximately 1.2ms
3-5V
AZ_SHP_OUTB
0-0.5V
D4061-1
Figure 9. AZ_SHP_OUTB / AZIM_DNEG
10us +
_ 0.5us
approximately 1.2ms
3-5V
AZ_SHP_OUT
0-0.5V
D4062-1
Figure 10. AZ_SHP_OUT / AZIM_DPOS
10us +
_ 0.5us
1/P.R. Frequency
3-5V
PRI_OUT
0-0.5V
D4063-1
Figure 11. PRI_OUT / PRI_DPOS
10us +
_ 0.5us
1/P.R. Frequency
3-5V
PRI_OUTB
0-0.5V
D4064-1
Figure 12. PRI_OUTB / PRI_DNEG
Service Manual 83139-1-Ch2 13
Part 2
Chapter 2
Display Connector (SK1)
Pathfinder Radar/Chartplotter Series
Part 2
Chapter 2
LNC Connector (P1)
Ref.
Signal Name
Type
State
Function
P1-1
P1-2
GND
60MHz IF
60MHz Intermediate
Frequency (IF)
Radar received
signal input
N/A
The down-converted received radar signal
from the LNC at 60MHz carrier frequency.
P1-3
Not Connected
N/A
N/A
N/A
P1-4
RF_ATTENV
Analogue control
voltage output
0 - 10V
A control voltage to apply RF attenuation to
the LNC limiter diodes.This function is not
used by SL72 and SL74 systems.
P1-5
TUNE_V
Analogue control
voltage output
4 - 24 V
A control voltage that is applied to the LNC
VCO (Voltage Controlled Oscillator) to
maintain the tuning of the IF input to
60MHz.
P1-6
GND
Analogue output
0V
Analogue ground reference for the LNC
supplies.
P1-7
+5V
Analogue Output
(switchable)
0V in standby mode
+5V in transmit mode
The 5v supply for the LNC. It is switched off
in standby mode to save power.
P1-8
-5V
Analogue Output
-5.9V nom.
The -5.9V supply for the LNC
-5V
GND
+5V
RF_ATTENV
TUNE_V
GND
N/C
60MHzIF
D4065-1
Figure 13. LNC Connector P1 connections as viewed from component side of board
Mod / IF Interconnect (P4)
This connector P4 is pin to pin identical to CN2 connector on the MOD / PSU PCB. See MOD / PSU
interface section for details.
2.5 IF Receiver – Circuit Description
Main Receiver
The prime function of the IF receiver is to provide low noise amplification and logarithmic detection
of the 60MHz IF (Intermediate Frequency) Radar received signal, to give a video signal output
suitable for displaying on the Radar screen (after digital processing at the display).
The receiver provides low noise amplification, dynamic IF gain control (STC) and selectable IF
bandwidths to optimise target detection for all ranges and for various sea and weather conditions.
The following summarises the functions of the circuitry.
A low noise amplifier (AR1), is situated prior to an adjustable gain monolithic microwave integrated
circuit (MMIC) amplifier stage (U9 and U10) in order to define the noise figure of the system. This
incorporates the relevant circuitry to provide fast gain control via the STC generator.
General amplification and attenuation control is also provided by the cascaded MMIC amplifiers U9
and U10 in conjunction with factory-tuned inductors (L4, L10 and L11) and capacitors to tailor the
bandwidth characteristics of the circuit.
14 Service Manual 83139-1-Ch2
Chapter 2. Technical Description
IF Bandwidth switching between 12MHz and 3MHz is configured to provide matched filtering for the
shorter 80ns and 250ns pulses respectively which is automatically set when the Radar range is
adjusted. Gain is increased accordingly to maintain a relatively constant noise power at the receiver
output.
A switched video filter is used in conjunction with the 3MHz IF filter to provide matched filtering for
the longest 700nS pulse. This is typically 0.69MHz wide
Remaining variations in noise power as a consequence of the different signal bandwidths (i.e. noise
power is directly proportional to bandwidth) are adjusted in the display.
N.B.The variable inductor coils L4, L10 and L11 are preset at the factory.They require
specialist equipment for tuning and must not be adjusted by the service engineer.
The PRI rates and video noise can be observed at the appropriate connectors (see interface
section) for the different range settings as follows:
Summary of bandwidths, pulse widths and PRI rates
Radar Range Setting
IF BW
Video BW
Pulse width used
PRI rate
Video Noise level
0.125 to 0.75 nm
12MHz
12MHz
80ns
2250 Hz
>500mV pk-pk
1.5 and 3nm
3MHz
12MHz
250ns
1500 Hz
>500mV pk-pk
6nm to max range
3MHz
0.69MHz
700ns
750 Hz
>250mV pk-pk
Autotune Receiver
The autotune receiver provides frequency selective peak detection of high level ‘main-bang’
transmitter pulses. This is achieved using a high impedance branch from the main receiver input
with a transistor/diode based amplifier/detector circuit (Q31, Q32, D16, Q33, Q37). The detection
frequency bandwidth of the autotune receiver is set at the factory using variable inductors L7, L8
and L9. The output of the receiver is buffered (U6A) and passed to the scanner microprocessor. A
tuning algorithm is then performed at the display to set the difference frequency between the
magnetron and VCO (Voltage Controlled Oscillator) to a fixed IF frequency of 60MHz using the
TUNE_V control line P1 pin5. Both coarse and fine adjustment are provided by the microprocessor
to allow for initial setting and subsequent fine tuning.
N.B. The variable inductor coils L7, L8 and L9 are preset at the factory.They require specialist
equipment for tuning and must not be adjusted by the service engineer.
STC/Main Bang Suppression (MBS)
The STC circuitry consists of a logarithmic function generator split into four outputs and multiplied by
4, 3.2 and 2 to generate the respective R4, sea clutter and rain curves respectively.
These curves are offset as requested via processor/operator demands and then combined to
provide an output equal to the greatest of the inputs. A curve splitter and linearisation circuits are
used to match the output control levels to the characteristics of each attenuator.
Service Manual 83139-1-Ch2 15
Part 2
Chapter 2
A ‘fast time constant’ circuit is used to provide a continuously variable high pass filter to provide
some immunity against the bulk effects of rain.
Pathfinder Radar/Chartplotter Series
General STC Characteristics
MBS
Decreasing
Attenuation
Curve amplitude
variations
4
STC - R decay
3.2
Sea clutter - R
decay
2
Rain clutter - R decay
Fixed gain
Part 2
Chapter 2
Combined curve generated as an output equal to the greatest of the inputs
Time
D4066-1
Figure 14. General STC Characteristics
Main bang suppression amplitude and duration controls are configured so as to override these STC
controls.
For low values of attenuation the attenuation is applied to the Monolithic amplifiers in order to
preserve system noise figure. At higher values of attenuation the attenuation is divided between the
IF pin attenuator (D17) used to control the first IF amplifier stage, and the Monolithic amplifiers.
Microcontroller
The microcontroller subsystem, using an NEC 78054 device, is integrated onto the IF receiver
board and provides the following functions :•
Generates analogue control voltages via a multi channel Digital to Analogue Connector (DAC)
for all user and automated scanner adjustments
•
Reads the tune indicator input and adjusts tune control voltage as necessary.
•
Controls modulator pulse width selection.
•
Generates stepper motor pulses
•
Generates Azimuth pulses for display synchronisation.
•
Generates the PRI (Pulse Repetition Interval) pulses to fire the magnetron, start the STC cycle
and synchronise the display.
•
Buffers the Ships Heading Pulse from the MOD/PSU PCB for synchronising the display.
•
Communicates with the display via a serial interface.
Initial Scanner set up (EEprom stored values)
The scanner has non volatile storage (EEprom U18) for the following items:•
Optimum VCO coarse and fine tune settings for Short, Medium and Long pulses
•
MBS Duration and Amplitude for Short, Medium and Long pulses
•
Range Zero Offset (adjusted by Display Timing function in Advanced settings Menu) for Short,
Medium and Long pulses
•
Stepper motor ramp time and pulse period - pre-set at factory - non adjustable
•
Azimuth zero offset (adjusted by Bearing Alignment function in Radar Set Up Menu)
16 Service Manual 83139-1-Ch2
Chapter 2. Technical Description
•
PRI Jitter Offset - used to help with interference rejection.
•
STC Preset Max - a preset level of R4 clutter curve is set to equalise close target returns
•
Scanner Size - storage of the antenna size fitted to the Scanner - used to set Max Range for
Display
•
Modulator Power - The power of the modulator in kW - also used to set Max range for Display
Due to temperature variations affecting the LNC, the VCO tuning values are adjusted by the display
when Auto mode is selected to give optimum tuning. The present optimum value is stored when a
range change (i.e. transmit pulse length change) is made, so that when the range is selected again,
the auto-tune function is at a better starting point. Normally this adjustment is made just to the fine
tune value for each pulse length. Occasionally, a change in coarse tune may be necessary. If tuning
problems occur, the Tune Preset function in the Advanced Settings Menu provides a manual way of
adjusting the coarse tune used working value.
The Range Zero Offset is adjusted manually from the display Advanced Settings Menu (Display
Timing) as part of the normal Radar installation procedure. If the inter unit cable is kept to the
supplied length the Display Timing should not normally need adjusting.
STC preset maximum is set at the factory, however the STC preset value can also be changed via
the Advanced Settings Menu.
When a Factory Reset is performed (press MENU, select SYSTEM SET UP, the press and hold
MENU for 5 second countdown) the scanner copies the Factory set values back into the used
working locations of the EEprom so the scanner and display are as they were set up when they left
the factory.
The EEprom also stores the scanner Build Standard information that is accessible through the
Diagnostics Menu - see chapter 4 - fault finding.
2.6 Antenna / Rotary Joint Assembly
The scanners use either 18" or 24" microstrip patch arrays
The primary specifications for the antenna / rotary joint assembly are as follows :Parameter
18” Radome
24” Radome
Operating frequency
9.410GHz ± 63MHz *
9.410GHz ± 63MHz *
Azimuth beam angle
5.2° nom
3.9° nom
Elevation beam angle
<28° nom
<28° nom
Antennae gain across bandwidth
22.3dB nom
22.9dB nom
Return loss
>15.0dB
>15.0dB
Sidelobe levels
>22.0dBc
>22.0dBc
* Bandwidth requirements are defined by the magnetron uncertainty
Figure 15. Antenna Outline Performance
Service Manual 83139-1-Ch2 17
Part 2
Chapter 2
The above stored parameters each have a factory set and used working location. These values are
set at the factory and are optimised for each individual scanner unit to provide optimum
performance and a good starting value when the Radar system is first operated. However, the VCO
tuning, range zero offset and Azimuth zero offset used working values are adjustable from the
display during Radar operation.
Pathfinder Radar/Chartplotter Series
2.7 Scanner Display Connection
The scanner / display interface is a universal link between any display and any scanner. It consists
of a single, multi-core cable with a single moulded plug at the display and multiple connections at the
scanner:
•
Video, Serial bus, PRI, Azimuth/Ships heading pulse
•
Power.
A moulded plug at the display provides the necessary sealing against the environment, whereas at
the scanner this is provided with a compression cable gland, push-fit connector for signal (8 way)
and sprung loaded connectors for power (2/4way).
Part 2
Chapter 2
The cable consists of the following cores :
1. 75 ohm coaxial cable carrying the 1.75V peak to peak video signal from the scanner (pins
7and8).
2. Twisted pair cable carrying the 5V differential azimuth and ships heading reset synchronising
signal from the scanner (pins 1and2).
3. Twisted pair cable carrying 5V differential PRI pulse synchronising signal from the scanner (pins
5and6).
4. Twisted pair cable carrying 5V differential, bi-directional serial communications signal (RS485)
between scanner and display (pins 3and4).
5. 8.7V-32V DC at scanner
With a standard 1.5 metre power cable, the maximum cable length between scanner and display is
35 metres. Combinations of inter-unit cables and their effect on power cable extensions (if any) are
discussed in Section 6.5, Inter-Unit Cable and Power Cable, in the HSB Series Pathfinder Radar
Owner's Handbook.
18 Service Manual 83139-1-Ch2
Chapter 3. Fault Finding
Chapter 3. Fault Finding
This chapter details the fault finding and repair issues for the Radome Scanner Units.
Please read the 3.1 Safety Notices and 3.2 General Notes below before commencing a service
operation. You should also read the 3.3 Built-in Testing/Diagnostics section as this will be of use in
many cases. Begin the fault finding procedure by refering to the System Trouble-shooting Check
List in Part 1, Section 3.5 which will advise on the appropriate course of action.
3.1 Safety Notices
When the display unit is powered with the case opened GREAT CARE MUST BE
TAKEN as the unit contains DANGEROUS HIGH VOLTAGES in the circuitry and
connections to the Cold Cathode Fluorescent Lamp (CCFL). Voltages in excess of
700 Volts may be present on connector SK9 and its associated cable.
The radar scanner also contains DANGEROUS HIGH VOLTAGES in the vicinity of
the high voltage power supply unit, Modulator and magnetron connections.
DANGER
Non-ionising Radiation
The radar scanner emits non-ionising radiation from the magnetron, circulator and
antenna assemblies. There are also low levels of ionising radiation (x-rays) in
close proximity to the magnetron when it is transmitting. It should not be operated
in transmit mode near to any persons, or within enclosed buildings.
3.2 General Notes
1. IMPORTANT. Whenever the microwave core assembly is removed from the radome
assembly the 4 foot seals must always be renewed to guarantee the water seal integrity
of the radome unit.
2. See Replacement of Parts notes and exploded views in Chapter 5 of Parts 2 and 3 for guidance
in dismantling of the radar.
3. The Connector / pin labelling convention used in this manual is as follows :
J4-6 means ‘connector J4, pin 6’.
4. When measurements to Picoflex ribbon cable connectors are specified, these can usually be
made by carefully probing the slots in the cable connector. Pin 1 is marked by the red cable
stripe.
5. Video Noise tests. A number of diagnostic procedures make reference to whether video noise
can be observed. The procedure for verifying this is as follows: With the Sea Clutter and Gain set
to manual, as the Gain is gradually increased the screen should show increasing ‘speckle’
corresponding to increased video noise, indicating that the IF receiver is driving the video signal.
Under normal circumstances the range of adjustment over which the screen goes from white to
black is around 10% of Gain adjustment. If the video signal is not present this will occur over 1 or
2 % of Gain adjustment.
6. Normal Motor Operation. When the radar is switched on the motor commences rotation. The
motor starts at a reduced speed for a few seconds and then accelerates to full speed (24 r.p.m.).
The motor runs for the full warm-up countdown period, and for approximately 1 minute
afterwards with the unit in standby. This is done to allow the microprocessor on the IF receiver to
Service Manual 83139-1-Ch3 19
Part 2
Chapter 3
The following checks are intended only for qualified service technicians.
Pathfinder Radar/Chartplotter Series
measure the rotation speed of the antenna and then set the correct rate of Azimuth pulses for
synchronising the display. This also allows the display sweep to be in sync immediately if
transmit mode is entered within the 1 minute period. To save power the motor is stopped after the
1 minute period if the unit is left in stand-by mode. In this case the motor will re-start in the same
ramped speed fashion when transmit is entered, causing a few seconds delay before the display
sweep is in sync with the antenna rotation.
Part 2
Chapter 3
7. The Display unit may be powered with the case folded open after the rear case screws have
been removed. If necessary the CPU PCB may be operated unscrewed from the moulding if
great care is taken to ensure it does not short-circuit to any other pcb. Under no circumstances
should the unit be operated without the LCD module plugged in to the CPU assembly
(connector J8) - to do so can damage the CPU PCB assembly.
8. Both the scanner and display unit operate from an internally isolated PSU. Thus ships battery
voltage measurements must be made with reference to the ships battery negative, whereas the
internally derived PSU outputs must be made with reference to the secondary ground. For the
display unit this can conveniently be probed at the ‘GND’ test pad near J7 on the CPU PCB. For
the scanner unit this can be conveniently probed from the metal casting of the scanner assembly
which is connected to the secondary GND. Unless otherwise stated measurements given in the
text are relative to the secondary grounds.
9. When switching the display unit on/off repeatedly you will notice that it is necessary to wait for
several seconds after switching off before the unit can be switched on again from the POWER
key. This is quite normal.
3.3 Built-in Testing / Diagnostics
The Pathfinder series Radars and Chartplotters incorporate a diagnostics menu to aid the service
engineer in finding some of the possible faults that could occur with the system.
The diagnostics menu can be accessed from either standby or transmit modes by the following key
sequence:
Press the MENU key. Press the RADAR SET UP or CHART SET UPsoft key. Press and hold
ENTER for approximately 5 seconds - a new set of soft key options will appear at the bottom of the
screen. Select BUILT-IN TEST.
Note:
Although all display variants can access the diagnostic menu, a repeater display or a RC520 will
only give very limited data.
See Diagnostics Menu - detailed description at the end of this chapter (section 3.6) for a full
desciption of its features.
3.4 Master and Repeater LCD Displays
When two displays are connected via the HSB bus, it is necessary, prior to isolating the fault to the
scanner or the display, to determine which display is the master i.e. connected to the scanner. In the
event that the rear of the units are not easily accessible, then this may be determined by powering
both displays on and waiting for the WARMING UP banner to count down to zero.
Power one of the two units off.
20 Service Manual 83139-1-Ch3
Chapter 3. Fault Finding
A message HSB LOST will be displayed and the alarm will sound on the other unit for about 5 seconds. If
this unit then shows the message STANDBY it is the Master display.
It will be possible to use scanner from the master display.
If the unit remaining powered up is the repeater, again a message HSB LOST will be displayed, and
the alarm will sound for about 5 seconds. If the unit then displays SCANNER NOT RESPONDING
then it is either a slave or the scanner is faulty. Repeat the procedure above on the other unit to
determine if the fault is in the repeater or the scanner.
3.5 Check Lists
SCANNER NOT RESPONDING message displayed or Start-up countdown restarts unexpectedly
External Checks
1. Check the inter-unit scanner cable is correctly fitted and pushed home at the rear of the display unit.
4
2
1
5
8
3
6
9
11
13
7
10
12
D4083-1
Figure 15. Scanner cable end connector
No.
Function
Colour
1
I/F Video information from scanner
Coaxial inner
2
I/F Video ground
Coaxial outer
3
Battery negative (filtered) to scanner
Black
4
Transmit trigger pulses from scanner
Orange
5
Battery negative (filtered) to scanner
Black
6
Command/data link to/from scanner
Green
7
Transmit trigger pulses
Yellow
8
Screen
No insulation
9
Battery positive (filtered, switched) to scanner
Red
10
Command/data link to/from scanner
Blue
11
Battery positive (filtered, switched) to scanner
Red
12
Azimuth and ship’s heading pulses from scanner
Violet
13
Azimuth and ship’s heading pulses from scanner
Grey
2. Check the scanner cable for signs of damage / corrosion.
3. Check the unit is correctly supplied with power :Voltage at power cable socket is between 10.7 and 32Volts (pins 5 and 3). If not check the
integrity of the power cabling to the radar system.
Service Manual 83139-1-Ch3 21
Part 2
Chapter 3
Check List 2
Pathfinder Radar/Chartplotter Series
4. With scanner cable removed measure the supply voltage on display cable plug at the rear of the
display unit and check it reads between 10.7 and 32 Volts (power pins may be identified by their
larger diameter compared to the signal pins). If not see Display Check 1 on following page.
5. Now check scanner communications link. With scanner cable disconnected from rear of display
measure resistance between pins 6 and 10 of scanner cable plug. A reading of approximately
160 W should be obtained. If not see Scanner Check 1 on following page.
Part 2
Chapter 3
6. Now check display communications link.
With scanner and power cables disconnected from rear of display measure resistance between
pins 6 and 10 of the scanner cable plug at the rear of the display. A reading of approximately 160
W should be obtained. If not see Display Check 2 on following page.
7. Turn the display unit on with the scanner disconnected. Wait until the “scanner not responding”
message appears then enter the Diagnostics menu. Check the Display Comms test result. A
pass indicates the display is probably OK and the fault lies in the scanner power supply or
communications link.
8. Reconnect the scanner cable. Remove the radome cover. Switch the unit on but ENSURE THE
UNIT IS NOT IN TRANSMIT MODE. Check that the voltage at CN-1,the power cable connector,
is greater than 8.7 Volts. If it is then see Scanner Check 2 checklist, or if the display countdown
restarts unexpectedly then see Display Check 3 . If less than 8.7 V is measured then the fault
could be excessive voltage drop in the inter-unit scanner cable due to damage or corrosion.
Repair or replace cable if necessary.
9. An excessive voltage drop could also be due to the scanner drawing excess current. If there is
just a simple communications fault, all the scanner functions will be off and it will consume
approximately 2.3 Watts. e.g. at 8.7 V it would draw 0.27Amps. Use an ammeter to measure the
current drawn at CN1, and hence calculate the power. If the power is OK then proceed with
Scanner Check 1. If the power consumption is excessive then proceed with Scanner Check 2.
Display Circuit Operation
The ships supply connects on the PSU board via solder buckets to the rear panel connector. Power
is applied to the units PSU when the internal relay closes. The relay is driven by either the power key
via circuitry on the CPU board, or by the micro itself. Thus initial switch on occurs when the power
key is depressed, causing the relay to close. The software then runs and holds the relay closed. At
switch-off the software shuts the unit down, then opens the relay.
Display Internal Checks
For all the following internal checks, with the display unit opened out and with all connectors still in
place, attach a ships power cable to the rear panel connector and switch the supply on.
Display Check 1 - Display has no power at scanner plug at rear of display
1. Check that the power reaches the Power / NMEA connector solder buckets on the PSU board. If
not then there is a failure of the power / NMEA connector. The solder buckets of this connector
may be probed with the CPU board in place. The connector is visible between CPU connectors
J8 and J4 on the PSU board. The battery power pins are those with the thick pcb tracks running
to them. If an incorrect voltage is measured then disassemble the rear cover assembly and
check the rear panel connector for signs of corrosion / damage.
22 Service Manual 83139-1-Ch3
Chapter 3. Fault Finding
Display Check 2 - Display communications check
1. Check resistance at CPU board connector J4 between J4-11 and J4-12 is approx. 160 W . If so
must be cable fault either on rear panel bucket connector on PSU board or ribbon cable to CPU
J4. Check for damage or corrosion and replace as necessary.
Display Check 3 - Display countdown restarts unexpectedly
1. Check that the Power cable between the PSU board PL7 and the CPU board J7 is connected,
with no breaks in any cores.
Scanner Internal Checks
Switch the system off at the boat’s distribution panel and disconnect the scanner cables to allow the
scanner unit to be removed to a dry place were it can be worked upon. Remove the radome cover
and microwave core assembly.
Note: The 4 foot seals must always be renewed to guarantee the water seal integrity of the radome
unit.
1
2
IF Receiver connector
3
4
5
6
7
8
D4094-1
Figure 16. IF Receiver connector SK1
Scanner Check 1 - Scanner communications checklist
1. Check connections at scanner 8-way connector with the radome cover removed. Particularly
check pin 3 (blue) and pin 4 (green) for damage or corrosion. If faulty repair or replace 8-way
Molex connector (p/n R126).
2. Measure resistance between 8-way Molex connector, SK1-3 and SK1-4 and check for
approximately 160 W . If resistance measurement wrong then replace IF PCB assembly. If
correct then fault must lie within the inter-unit scanner cable, replace.
Scanner Check 2 - Scanner power checklist
1. Check the internal receiver power supplies on the Mod/PSU. See Receiver Power Supply
Output table in Mod/PSU PCB Checklist 9. If OK proceed to next test.
2. Check power to IF PCB. Remove IF metal cover plate. Check if +5 V is present at P4-2. If it is
present the IF receiver is assumed to have a faulty communications circuit and should be
replaced. Otherwise if + 5V was not measured then check / replace the ribbon cable assembly
connected to P4.
Service Manual 83139-1-Ch3 23
Part 2
Chapter 3
2. Power the display and press the Power key. With a ground reference on J7- 2, PGND, of the
cable check that the voltages shown in Checklist 10 for CPU Power - J7 are present. If all are
correct then proceed to next test, else there is a failure of the PSU PCB.
Pathfinder Radar/Chartplotter Series
Check List 3
Radar Target Image blank / faulty (missing radar targets, no radar
scan, poor performance, etc.)
External Checks
Part 2
Chapter 3
1. Check that the Radome lid is fitted. If the Radome is run in bright daylight with the lid removed,
the ship’s heading, Opto PCB may generate additional pulses, causing the radar sweep to reset.
2. It may be desirable to carry out a full Reset of the Radar system before continuing with the
checks, indeed this may cure the fault. Note however that this will also reset Bearing Alignment,
Display Timing, Tune and STC Preset to their factory defaults, and therefore these may need to
be set up again as for a new installation.
To perform a system reset:
- Power-up the radar system and allow the 70 second countdown period to complete.
- Press MENU and select SYSTEM SET-UP.
- Press and hold the MENU key until the Reset countdown has reached zero. Release the key,
the radar system will reset and restart the 70 second countdown.
- The scanner has now been reset to factory settings.
- Check if the fault symptoms have disappeared.
3. Check that the coarse tune setting of the Radar is correct, by adjusting the Tune Preset value in
the Advanced Settings Menu. If still no targets appear or Radar image is poor then continue with
this checklist, but firstly restore the Tune Preset to its previous value using the softkey
“RESTORE PREVIOUS”.
4. If the fault persists see the Diagnostics Menu flowchart A
5. If the unit is still faulty see Radar image fault flowchart E
24 Service Manual 83139-1-Ch3
Chapter 3. Fault Finding
SYSTEM FAULT FINDING DIAGNOSTIC MENU
This indicates there is a
bad connection in the PRI
and AZ_SHP pairs of
wires between the
scanner and display
Enable the diagnostics menu using the
following key sequence:
- Press the "MENU" key.
- Press the "RADAR SET UP " softkey.
- Press and hold ENTER for approx 5
seconds.
- Select "BUILT-IN TEST" softkey.
Probable fault symptom(s):
i) No radar picture or video noise
- bad PRI or AZ_SHP
ii) Missing or jumping sectors
- bad AZ_SHP
iii) Spoke-like interference and/or blank
hole to 0.7nm - bad PRI
Check 8-way connector at SK1 in the
radome and inter-unit cable for
damage (Pins 1&2, 5&6). repair /
replace as necessary. Also check
continuity of inter-unit cable and from
Pins 4,7 and 12, 13 of display socket
to CPU PCB.
Check all the following items in the order
shown for PASS / FAIL.
NOTE: See main text for further
descriptions of diagnostics menu.
CABLE TEST STATUS
Part 2
Chapter 3
A
NOTE: It is possible that an item could
indicate fail but radar operation is normal.
For this reason the fault symptoms that
would be observed if that item has failed are
described. Always try to confirm the fault
symptom before proceeding with fault
finding. In any case all fails should be listed
on the service fault report form.
POWER UP RADAR
When the next 70sec countdown has
finished put radar into transmit and set to
each of 1/8nm, 3nm and 6nm ranges for at
least 5 secs. This allows the modulator
current value in the diagnostics menu to
be updated for each pulse length.
FAIL
SCANNER RESET
SCANNER RESET
RECEIVER SUPPLY 12V
RECEIVER SUPPLY -5.9V
RECEIVER SUPPLY 5V
SHIP HEADING SENSOR
MAGNETRON HEATER
EEPROM WRITE
EEPROM READ
FACTORY SETUP / IF TUNED
MODULATOR CURRENT SP, MP, LP
FAIL IF VALUE READS 1 OR MORE TIMES
B
RECEIVER SUPPLY FAILURE
FAIL
C
FAIL
FAIL
SHIP HEADING
SENSOR FAIL
This indicates that the
display is not receiving
ships heading pulses.
Probable fault symptom:
Radar sweep appears
erratic, repeatedly
stopping.
D
FAIL
Check Magnetron
Interface section (CN7-1,
CN7-2), and signals
HEATER_EN_N (CN2-4)
and HEATER_OK (CN2-3)
of the MOD/PSU PCB
checklist 9
FAIL
FAIL
FAIL
This indicates there is an EEprom
memory fault with IF Receiver PCB.
See diagnostics menu description in
this chapter for more details and
replace IF Receiver PCB.
FAIL
This indicates there is a fault with the
setup of the IF Receiver PCB or an
untuned replacement PCB has been
fitted. Replace IF Receiver PCB.
CHECK
VALUES
The displayed value is a failure if on
one or more pulse lengths it is outside
the range given in the diagnostics
menu description Figure 26. However,
if the scanner software version is 1.14
then the displayed values will be
incorrect - the measurements can be
made directly in the scanner if a fault is
suspected- see MOD/PSU checklist 9,
Modulator/Control Status table.
FAIL
MOD/PSU fault
suspected replace
MOD/PSU.
D4073-1
Service Manual 83139-1-Ch3 25
B
SCANNER
RESET
Indicates that the micro
processor on the IF
receiver PCB in the
scanner is resetting
unexpectedly.
Problem could be ships
power supply,
magnetron or MOD /
PSU, IF receiver or
LNC.
26 Service Manual 83139-1-Ch3
Ships supply problem voltage too low for
radar operation.
NO
Check
ships supply
at the display
is 10.7V
minimum.
YES
Must be a micro reset
problem on the IF
receiver - replace IF
PCB
Suspect excessive
current in scanner,
check all interfaces in
Checklist 9.
Cable OK
May be excessive
voltage drop in inter unit
cable. Check
connectors and cable
for corrosion / damage.
Repair or replace cable.
NO
Check that
voltage on power
core(s) at CN1 in
the radome is
8.7V volts
minimum.
NO
YES
Is
LNC +5V
shorted?
YES
Faulty LNC replace LNC.
Suspect problem is with
magnetron or MOD /
PSU, IF receiver or LNC.
Part 2
Chapter 3
Remove IF receiver PCB
from the core such that
LNC is disconnected.
Check for short from +5V
to GND at LNC
inter-connector in the
core (see interface
section of the technical
description for pin-out
diagram).
Remove cover to
expose underside of IF
receiver PCB.
Suspect problem on IF
receiver or LNC.
NO FAULTS
FOUND SO
FAR
Firstly check the receiver
supplies and magnetron
interface on the
MOD/PSU PCB checklist
9 at the end of this
chapter.
D4075-1
Pathfinder Radar/Chartplotter Series
C
Fault with 5V switch
on IF receiver.
Replace IF receiver.
Probable symptom:
No radar targets and
no video noise.
Indicates that the
switched 5V supply on
the IF receiver PCB has
failed to switch on.
Receiver supply 5V
Receiver supply -5.9V
Receiver supply 12V
RECEIVER SUPPLY FAILURE
FAIL
FAIL
FAIL
Fault must be with 12V
switch or 5.9V rail on IF
receiver - replace IF
receiver PCB.
Indicates that the - 5.9V
supply to the IF receiver
PCB is faulty.
Indicates that the
switched 12V supply on
the IF receiver PCB has
failed to switch on.
CABLE GOOD
Remove and check
ribbon cable assembly
for continuity / shorts.
Replace as necessary.
BAD
-5.9V
failure only.
Remove IF receiver
PCB from the core such
that LNC is
disconnected.
Remove cover to
expose underside of IF
receiver PCB.
Fault must be local to IF
receiver, ribbon cable, or
LNC.
GOOD
MOD/PSU
good?
Part 2
Chapter 3
12V and
-5.9V failure.
Firstly check the
receiver supplies table
of the MOD / PSU PCB
checklist 9.
NOTE: With V1.14 scanner software the
Receiver Supply items may occasionally
read FAIL when they are okay.
If any other item in diagnostics menu is
FAIL, then persue that fault first, else
enter transmit mode several times to
check if failure is consistant before
continuing.
Probable symptom:
No radar targets and
no video noise.
NO
Faulty LNC - replace
LNC PCB.
YES
Is
LNC - 5.9V
shorted?
Check for short from
-5.9V to GND at LNC
interconnector in the
core - see Figure 13 in
interface section of the
technical description for
pin-out diagram.
Replace
MOD/PSU PCB.
D4074-1
Chapter 3. Fault Finding
Service Manual 83139-1-Ch3 27
28 Service Manual 83139-1-Ch3
Replace
drive
belt
STEPPER
MOTOR
FAULT
YES
BAD
Suspect ship sensor
PCB , connector to
MOD/ PSU or to IF
receiver, stepper motor
or drive belt problem or
antenna seizure.
Check Stepper Motor
Control and Stepper
Motor Interface tables
of the MOD/PSU PCB
Checklist 9. Replace if
necesssary
D
SHIP HEADING
SENSOR FAIL
Antenna bearing
seizure. Replace
antenna assembly.
NO - STIFF
OR SEIZED
Spin antenna
by hand. Does
antenna spin
freely?
Slip drive belt
off antenna
pulley.
GOOD
Check
condition
and correct
attachment
of antenna
drive belt.
Remove
radome
cover.
Power
off
radar.
Suspect IF receiver
PCB shp interface.
Replace IF receiver
PCB.
Suspect stepper motor
or drive belt problem or
antenna seizure.
NO
During 70
second STANDBY
countdown, does
antenna rotate at
all?
SIGNAL GOOD
YES
Check 18 way ribbon
cable assembly for
damage, repair, replace
if necessary.
Suspect 18 way ribbon
cable assembly or
MOD / PSU PCB.
NO SIGNAL
Check pulse
signal is good at
Pin 15 of IF
connector P4.
Could be opto PCB,
MOD/PSU PCB, IF PCB
or connector problem.
YES, ANTENNA CONTINUOUSLY
RAMPS UP IN SPEED THEN
RESTARTS.
Part 2
Chapter 3
Remove MOD / PSU
PCB. Remove IF
receiver cover. Leave
all connections intact.
Suspect IF receiver
PCB or cable.
NO FAULT
FOUND SO
FAR
Firstly check Ships
Heading Sensor OptoSwitch Interface and
Ships Heading Output
tables of the MOD/PSU
PCB checklist 9.
D4076-1
Pathfinder Radar/Chartplotter Series
Chapter 3. Fault Finding
RADAR
IMAGE
FAULT
E
IDENTIFY SYSTEM FAULT
F
No targets, but video noise present
See "General Note" at the beginning
of this chapter for definition of "video
noise".
G
Reduced target level on any range and/or
poor long range performance
H
Part 2
Chapter 3
No targets and no video noise
Radar tuning problems
Fault symptoms:
i) Auto-tune function not
keeping good tune
ii) In manual tune signal
strength indicator bar
varying excessively even
when at best tune position.
STC / clutter control problem
Fault symptoms:
i) Target strength cannot be
equalised by STC preset
adjustment
ii) Sea clutter or rain clutter
control not working correctly
Done
Replace IF receiver
PCB
J
Suspect STC curve fault
on IF receiver PCB
D4077-1
Service Manual 83139-1-Ch3 29
NO TARGETS, BUT
VIDEO NOISE
PRESENT
Suspect magnetron,
MOD/PSU, LNC or
F
IF PCB, or antenna
fault.
Switch radar to
transmit, set tune to
auto, gain and sea
auto. In Advanced
Set Up menu adjust
display timing to 0m.
30 Service Manual 83139-1-Ch3
SS VALUE LESS THAN
70 AND T VARYING
WILDLY.
Suspect IF receiver
PCB fault. Replace
IF receiver.
IF receiver autotune
circuit must be detecting
signal ok. Therefore
magnetron must be firing
and LNC working.
Therefore fault must lie
on IF receiver gain or
video sections.
SS VALUE GREATER THAN 70 AND
T VARYING BY LESS THAN 10
i.e. AUTOTUNE ALGORITHM IS
LOCKED ON.
On 6 nm
range transmit,
note the values for
TUNE (T) and
signal STRENGTH
(SS).
YES
Suspect antenna
or circulator fault.
MAIN BANG VIDEO
NOT PRESENT
Call up the debug info
box by hidden key press
sequence:
- press MENU,
- select RADAR SETUP,
- press and hold CLEAR
for 5 secs. Use right
hand softkey to switch
debug box on.
NO
Use
softkey to
switch MBS off.
Does dark ring
appear?
MAIN BANG VIDEO
PRESENT
If symptom persists
replace IF receiver
PCB.
NO FAULTS
FOUND SO
FAR
Replace
magnetron.
FAULT SYMPTOMS
STILL PRESENT
Replace
LNC
FAULT SYMPTOMS
STILL PRESENT
Suspect
magnetron
or LNC.
Circulator note:The performance of the circulator may
degrade if excessive corrosion of the internal
surfaces occurs. In this case the circulator
should be replaced.
Inspect circulator
for internal
corrosion. Replace
if necessary - see
note below.
Suspect LNC to IF
receiver connector at
P1 or P7. Check for
damage / corrosion replace as necessary.
Check the modulator
control/status table of
the MOD/PSU
checklist 9. Replace
faulty unit / assembly
if appropriate.
Inspect antenna
patch array for
corrosion or
damage. Replace
assembly as
necessary.
Part 2
Chapter 3
D4078-1
Pathfinder Radar/Chartplotter Series
G
NO TARGETS AND
NO VIDEO NOISE
Suspect video cable /
connector, IF receiver,
MOD/PSU or display
problem.
Check for video
waveform on J4-1 in
the display. See
display CPU comms
table in Checklist 10
for typical waveform.
Replace IF
receiver
PCB.
Replace
MOD/PSU
PCB.
Check J4 connection
is firmly made. If OK,
then CPU is faulty.
Replace CPU PCB.
GOOD
Waveform good?
BAD
BAD
Service Manual 83139-1-Ch3 31
Part 2
Chapter 3
Suspect problem
with video circuit
on IF receiver.
GOOD
MOD / PSU good?
Inspect inter-unit cable
(video cores) and Pins
1 & 2 of display rear
connector for damage
or corrosion. Repair /
replace as necessary.
Check the Receiver
Power Supply Output
table of the MOD/PSU
PCB checklist 9.
Suspect problem with
IF receiver or supplies.
FAULT SYMPTOMS
STILL PRESENT
Inspect video signal
connections (Pins 7 &
8 at SK1) in the
radome for damage
corrosion. Repair /
replace as necessary.
D4079-1
Chapter 3. Fault Finding
H
Suspect limiter blown in
LNC, modulator,
magnetron or antenna /
circulator problem.
REDUCED TARGET LEVEL AND/OR
POOR LONG RANGE PERFORMANCE
32 Service Manual 83139-1-Ch3
Circulator note:The performance of the circulator
may degrade if excessive
corrosion of the internal surfaces
occurs. In this case the circulator
should be replaced.
Inspect patch antenna /
rotary joint assembly
and circulator for
damage/ corrosion N.B. remove circulator
for internal inspection.
Check Modulator
Control / Status and
Receiver Power Supply
Output tables of the
MOD / PSU PCB
Checklist 9.
NO FAULT FOUND SO FAR
Part 2
Chapter 3
Suspect LNC
limiter fault.
Replace LNC.
STILL FAULTY
Suspect Magnetron
fault. Replace
Magnetron.
D4080-1
Pathfinder Radar/Chartplotter Series
Chapter 3. Fault Finding
J
Problem is likely to
be"pulling" of the VCO
in the LNC due to stray
energy from the
antenna.
Part 2
Chapter 3
RADAR TUNING
PROBLEMS
Check all of the following:
1) The fixing screws for the LNC, LNC cover, circulator
and magnetron are tight
2) If the unit is a 24" radome then check that screening
can around cable interface on the outside of the core
is in place and secure
3) Remove antenna assembly from core and check that
the central pin that protrudes from the rotary joint is
not bent or damaged - if damaged replace antenna
assembly.
4) Check that the black foam RAM (Radio Absorbent
Material) is fitted and intact in centre of underside of
LNC cover - replace cover if necessary
5) That the gasket fitted between circulator and core at
the antenna waveguide port is intact - replace if
necessary
6) That the circular conductive gasket fitted on the
underside of the LNC pin is fitted and intact - replace
if necessary
7) That the "L-shaped" piece of RAM fitted to the core in
the IF receiver cavity is fitted and intact - replace if
necessary
STILL PROBLEMS
Replace LNC
D4081-1
Service Manual 83139-1-Ch3 33
Pathfinder Radar/Chartplotter Series
Check List 9
MOD/PSU PCB
General Information
Part 2
Chapter 3
To allow access to the MOD/PSU interface connections in this checklist the following procedure
should be used:
•
Turn off the display. Disconnect interunit cable at display.
•
Disconnect cable at the Radome and remove Radome to appropriate dry working area or
preferably a workshop.
•
Remove core assembly from Radome base (N.B. Circular foam seals around core feet will need
replacing on reassembly to ensure watertight seal - see general notes at the beginning of this
chapter).
•
Remove magnetron connetor CN6 to ensure tramsmission, is entirely disabled.
•
Invert unit, carefully supporting antenna and remove base cover to expose underside of MOD/
PSU PCB. Support unit (e.g. by holding casting gently in a large vice) on its side so that antenna
is free to rotate and the MOD/PSU PCB interfaces can be probed. For tests in stand-by mode
only, the MOD/PSU PCB may be removed from the core and placed on a suitable insulated
surface and the connections re-made to the core remotely, if this is more convenient.
•
A spare 10m (light) interunit cable should now be used to connect the core to the display unit.
•
Turn power on. Warning: Dangerous high voltages exist in the core assembly, avoid
touching MOD/PSU PCB with fingers whilst powered.
Magnetron Dummy Load
For some of the fault checks in this section it may be required to enable transmit mode to allow
proper diagnosis. Due to the hazard from the electromagnetic radiation from the magnetron and
antenna this should not be done. However with the magnetron disconnected at CN6, it is safe to
connect a dummy load to CN6 to electrically simulate the magnetron load.
A dummy load may be constructed and connected to CN6 as follows :12 ohm / 4W
CN6-1
1.5 kohm / 4W
CN6-2
GND
D4095-1
Figure 17. Magnetron dummy load
Note: For safety reasons the 1.5k resistor must withstand up to 5 kV pulsed, duty cycle 1/2000.
Long wire wound parts will usually suffice. In addition the load should be suitably insulated to
prevent High Voltage shocks. The GND connection is to the core casting (the screw fixing for the
magnetron cable screen wire adjacent to CN7 scocket may be used as a convenient attachment
point). The MOD/PSU PCB must be mounted in the core for these tests to ensure adequate
grounding.
34 Service Manual 83139-1-Ch3
Chapter 3. Fault Finding
1 2 3
CN2 (IF Receiver connector)
16 14 12 10 8 6 4 2
CN4 (Motor connector)
1 2 3 4 5 6
15 13 11 9 7 5 3 1
D4093-1
Figure 18. Mod/PSU Connector pins
Note: This PCB is conformally coated, thus use of a sharp DVM probe may be required to make a
good contact. Pin 1 of each connector is marked with a square pad on the PCB.
In general, perform the check in the order given, or if a particular fault is suspected go to that section.
Ship Supply Power Input
Ref.
Signal Name
Function
Status during standby
Fault Checks
CN1-5
CN1-6
CN1-7
CN1-8
+BATT_IN
Ships power i/p
10.7 - 32V
i) Check Power cores are connected in
correct polarity.
ii) Check connector for corrosion / poor
contacts - repair or replace
iii) If voltage is Low - check ship’s supply at
power cable display socket is within
operating spec (>10.7V) and inter unit cable
is good - corrosion or damaged cores could
cause excessive voltage drop.
CN1-1
CN1-2
CN1-3
CN1-4
-BATT_IN
Ships power return
–
–
Receiver Power Supply Output
Ref.
Signal Name
Function
Status during standby
Fault Checks
CN2-1
IF-5V
-5.9V power rail
to receiver
-6.4V to -5.6V
If voltages are out of spec, unstable or not
present:
CN2-2
IF+5V
+5V power rail
to receiver
4.7V to 5..3V
i) Power - off and remove modpsu –
disconnect IF receiver ribbon cable
CN2-4
IF+26V
+26V power rail
to receiver
25.0V to 29.0V
ii) Connect a 10ohm 4W resistor from +5V
pin to GND
CN2-6
IF+12V
+12V power rail
to receiver
11.2V to 12.4V
iii) Power-up and Re - check voltages
iv) If still out of spec then mod/psu board low
voltage supply is faulty - replace mod/psu
board
CN2-5
CN2-7
GND
GND
Isolated GND return
from receiver power
rails
GND
Service Manual 83139-1-Ch3 35
Part 2
Chapter 3
CN5 (SHP sensor)
Pathfinder Radar/Chartplotter Series
Magnetron Interface
Ref.
Signal Name
Function
Status during standby
Fault Checks
CN6-1
HEATER
Magnetron heater
/anode power
6.0 to 6.6V across
connector
(with magnetron fitted)
If voltage out of spec/not present:
i) Power-off and disconnect magnetron at
CN6, connect a 12 ohm 4W resistor across
CN6 socket.
CN6-2
HEAT/CATH
Magnetron heater
/cathode power
ii) Power-up and re-check voltage across
connector.
iii) If still out of spec then heater supply on
mod/psu is faulty - replace mod/psu
iv) If OK now then magnetron is faulty.
Part 2
Chapter 3
Ships Heading Sensor Opto-coupler Interface
Ref.
Signal Name
Function
Status during standby
Fault Checks
CN5-1
BZ
Opto emitter
connection
With antenna rotating,
signal should normally
be high with a low going
100ms pulse once
every 2.5 sec’s.
No pulse:
i) check +5V on pin 2 and GND on pin 3 first
ii) check CN5 connector is sound.
iii) If OK then faulty opto PCB
CN5-2
+5V
+5V to Opto LED
anode and collector
connection
4.7 to 5.3V
If 5V not present:
i)Disconnect opto connector and check
Receiver Supply outputs.
ii) If supply outputs OK and 5V still not
present - faulty mod/psu
iii) If 5V now OK then must be a short on
opto PCB assembly - replace opto PCB
CN5-3
SHGND
Current limited
Opto LED cathode
GND connection
GND
Check GND continuity
Ships Heading Output
Ref.
Signal Name
Function
Status during standby
Fault Checks
CN2-15
SHP_IN
Output of SHP pulse
With antenna rotating,
signal should normally
be high with a low going
100ms pulse once
every 2.5 sec’s.
If signal not present:
i) Check CN5 signals OK first
ii) If OK then remove IF PCB ribbon cable
from CN2 and recheck signal at pin 15
iii) If OK now then mod/psu PCB is good.
iv) If not replace mod/psu PCB
Stepper Motor Control
Ref.
Signal Name
Function
Status during standby
Fault Checks
CN2-12
MOTOR_EN_N
Enable Motor
Should be low during
70 sec countdown and
for 60 sec’s afterwards.
Else will go high to
disable motor.
If not Low;
i) Disconnect ribbon connector at CN2 and
check pin 12 on cable is low - if not then fault
on IF PCB
ii) Check connection to CN2 is sound - if OK
then fault on mod/psu board - repair or
replace
CN2-10
STEP_IO
Clock Input Pulses
from IF PCB used by
the mod/psu to
generate Stepper
motor drive pulses.
Input from IF PCB at
189 Hz ; 50% duty cycle.
Motor pulses will only be generated if the IF
PCB can see the pull-up resistor fitted to
this line on the mod/psu. Therefore:
i) Disconnect ribbon connector at CN2 and
check pin 10 on the mod/psu is high - if not,
then the mod/psu is faulty. Repair or replace.
ii) Check IF PCB ribbon cable and
connector at CN2 are sound.
iii) If sound and still no pulses -fault on IF
Receiver PCB.
36 Service Manual 83139-1-Ch3
Chapter 3. Fault Finding
Stepper Motor Interface
Signal Name
Function
CN4-6
STMO1
Phase A2 switch
Status during standby
PM3394A
ch1
ch1: dT=21.2ms dV=11.3 V
ch1: freq= 180 Hz
ch1: duty= 57.7 %
T
1
CH1 5.00 V=
MTB10.0ms- 1.94dv ch1+
Y/Div: Timebase: TRACE Trigger time & date
5.00 V 10.0ms
ch1
11:13:07:07 20-08-1997
Time of hardcopy:
11:13:13 20-08-1997
11.2V to 12.8V
Fault Checks
Whilst motor is enabled see scope trace. If
waveform is incorrect or not present check the
following:
1. Disconnect CN4. Check if motor shaft turns
freely by hand. If not, then motor is seized.
Replace motor.
2. Use an ohm meter to check motor winding
resistance. At motor cable connector measure
across:
Sockets 1 and 2 – 27W
Sockets 2 and 3 – 27W
Sockets 4 and 5 – 27W
Sockets 5 and 6 – 27W
If measurement is good, then MOD/PSU is
faulty. If measurement is bad, then motor is
faulty.
CN4-5
STMO2
Vmotor
If voltage low or not present:
i) Disconnect motor connector CN4 and
connect a load of 27 ohms (at least 6W
rating) from pin 5 or 2 to GND (chassis)
ii) Re-check voltage - if still bad then fault
with the motor power supply on the mod/ psu
iii) If OK then motor faulty - replace motor.
CN4-4
STMO3
Phase A1 switch See CN4-6
See CN4-6
CN4-3
STMO4
Phase B1 switch See CN4-6
See CN4-6
CN4-2
STMO5
Vmotor
See CN4-5
See CN4-5
CN4-1
STMO6
Phase B2 switch See CN4-6
See CN4-6
PSU Control/Status
Ref.
Signal Name
Function
Status during standby
Fault Checks
CN2-14
HEATER_EN_N
Enable magnetron
heater, modulator
PSU and stepper
motor PSU.
Should be Logic Low
input in standby and
transmit modes
If not Low:
i) Disconnect ribbon connector at CN2
and check pin 14 on cable is low - if not
then fault on IF PCB
ii) Check connection to CN2 is sound - if OK
then fault on mod/psu board - repair or
replace
Service Manual 83139-1-Ch3 37
Part 2
Chapter 3
Ref.
Pathfinder Radar/Chartplotter Series
Modulator Control/Status
Ref.
Signal Name
Function
Status during standby
Fault Checks
CN2-18
RADAR_TX_EN
Enable modulator (magnetron)
transmission - input
from IF PCB
This is Low during
standby, High in transmit
mode
With a dummy load
attached to CN7, check that
signal goes High in transmit
mode. If not faulty IF board .
CN2-9
CN2-11
PW0,
PW1
Selects modulator pulse width
as follows :80ns pulse (1/8 to 3/4 nm range)
250ns pulse (1.5 and 3 nm range)
700ns pulse (6nm to max range)
700ns pulse (not used)
PW0
PW1
0
1
0
1
0
0
1
1
Check PW0 and PW1 are
of correct status for the
range selected, if not:
i) Check CN2 cable and
connector are sound
ii) If not - faulty IF board
PRI_PLS
Normally high ,10us+/-0.5us low
going pulse. Frequency will be
varied according to pulse width;
80ns PRF = 2250Hz ;
200ns PRF=1500Hz,
700ns PRF=750Hz.
Rising edge triggers modulator
pulse.
This signal is not visible
during the 70 second
countdown but is switched
for the next 60 seconds.
During 60 second on period
if signal is not present:
i) Check CN2 cable and
connector are sound
ii) If not - faulty IF board
CN2-3
HEATER_OK
An output which indicates that
magnetron heater is connected
and drawing > minimum current.
Should be a logic High in
standby and transmit
modes
If signal is Low:
i) Check heater voltage on
CN7 first
ii) If OK then connect a
12ohm 4W resistor across
CN7 socket and re-check
CN2-3 voltage
iii) If still bad disconnect IF
ribbon cable and recheck
CN2-3.
iv) If still bad then Mod/psu
PCB is faulty, if OK then
fault at IF receiver (short).
CN2-17
MOD_ISENSE
Indicates peak magnitude of
magnetron anode current and thus
indicates approximately peak R.F.
power output.
This should be low in
standby. In transmit mode
refer to Modulator Technical
Description in Chapter 2.
Connect a dummy load to
CN7. In transmit mode
check voltage is in the
range as in Figure 7, in
Chapter 2.
CN2-16
MOD_SENSE1
Analogue voltage indicates
build standard.
N/A
–
CN2-13
MOD_SENSE2
Analogue voltage indicates
build standard.
N/A
–
Part 2
Chapter 3
CN2-8
Note: With V1.14 Scanner Micro Software the modulator current readings in the diagnostics menu
are incorrect. In this case check the voltage at Pin 17 CN2 of MOD/ PSU PCB. The voltage should
be within the limits given in the modulator technical description (Chapter 2) for MOD_ISENSE. The
unit must be powered and in transmit mode, but ensure magnetron connector CN7 is disconnected
and connect dummy load at CN7. Unit must be carefully supported to allow antenna to rotate.
38 Service Manual 83139-1-Ch3
Chapter 3. Fault Finding
3.6 Diagnostics Menu – detailed description
The diagnostics menu can be enabled as follows: Press MENU ➔ Press RADAR SET UP or
CHART SET UP ➔ Press and hold ENTER (for 5 seconds) ➔ Press BUILT-IN TEST
The menu lists the status of the following items:
1.
SCANNER BUILD STD
2.
SCANNER SW VERSION
3.
ESN *
4.
DISPLAY SW VERSION *
5.
SCANNER SIZE
6.
MODULATOR POWER
7.
HEATER HOUR COUNT
8.
DISPLAY COMMS *
9.
CABLE TEST STATUS
10.
RECEIVER SUPPLY 12V
11.
RECEIVER SUPPLY -5.9V
12.
RECEIVER SUPPLY 5V
13.
SCANNER RESET
14.
SHIP HEADING SENSOR
15.
MAGNETRON HEATER
16.
EEPROM WRITE
17.
EEPROM READ
17.
FACTORY SETUP
19.
IF TUNED
20.
MODULATOR CURRENT SP
21.
MODULATOR CURRENT MP
22.
MODULATOR CURRENT LP
23.
ROTATION TIME
24.
STC PRESET MAX
Part 2
Chapter 3
RC520, or a repeater display will only show data for these items marked*.
In general the status is updated each time that the menu is selected, such that the latest status is
shown where appropriate. In the description below the timing of when the items are monitored is given.
Service Manual 83139-1-Ch3 39
Pathfinder Radar/Chartplotter Series
1. SCANNER BUILD STD.
This item indicates the build standard of the Radar scanner (radome) that the display is connected
to. It is in effect a serial number that allows Raytheon to determine the Date of manufacture and
exact hardware build standard of the unit. It should be quoted on all Fault Feedback Forms returned
to Raytheon. This item is stored in the EEprom of the IF receiver PCB in the scanner, it is read from
the scanner once only at power-up.
2. SCANNER SW VERSION
Part 2
Chapter 3
This item indicates the software version number of the microcontroller on the IF receiver PCB in the
scanner. This item is stored in the EEprom of the IF receiver PCB in the scanner, it is read from the
scanner once only at power-up.
3. ESN
Display Electronic Serial Number. This item indicates the build standard of the Radar display unit. It
is in effect a serial number that allows Raytheon to determine the Date of manufacture and exact
hardware build standard of the unit. It should be quoted on all Fault Feedback Forms returned to
Raytheon.
4. DISPLAY SW VERSION
This item indicates the software version of the PROMs on the CPU PCB in the display unit. It is read
once only at power-up.
5. SCANNER SIZE
This item indicates the size of the radome antenna in inches. This item is stored in the EEprom of the
IF receiver PCB in the scanner, it is read from the scanner once only at power-up.
6. MODULATOR POWER
This item indicates the output power of the radome modulator and Magnetron in kW. This item is stored in
the EEprom of the IF receiver PCB in the scanner, it is read from the scanner once only at power-up.
7. HEATER HOUR COUNT
This item indicates the number of hours that the magnetron heater has been running for throughout
the Radar systems’ life i.e. the sum of the standby and transmit hours. It is incremented every 6
minutes (0.1 hour). This item is stored in the EEprom of the IF receiver PCB in the scanner, it is read
from the scanner once only at power-up.
8. DISPLAY COMMS
A display communications test is performed at power-up to check the display to scanner
communications link driver is functioning OK. If this shows a FAIL status then a SCANNER NOT
RESPONDING message will be shown on power-up. Refer to Checklist 2 for further diagnosis.
9. CABLE TEST STATUS
This item shows the status of the cable test function. This test checks that the PRI differential pair
and the AZimuth_SHP pair of wires linking the display to the scanner are making a good
connection. If a FAIL status is indicated check the condition of the inter-unit cable and the 8-way
40 Service Manual 83139-1-Ch3
Chapter 3. Fault Finding
Molex connector at SK1 in the Radome (pins 1and 2, 5 and 6). See flowchart for further diagnosis.
This test is performed once at power up only.
NOTE: Failure Symptoms. Failure of one of the AZ _SHP pair of wires (pins 1 and 2) can give an
effect in the Radar picture where certain sectors of the screen are updated rapidly while other are
“frozen” or blank. If both fail then no radar picture or video noise is seen.
Failure of one of the PRI links (pins 5 and 6), can give a “spoke type” interference effect in the Radar
picture, with possibly a blank “hole” in the centre of the screen up to approximately 0.7nm range. If
both fail then no radar picture or video noise will be seen.
This test checks the presence of the above supply voltages at the IF receiver. The test is performed
once, each time that transmit mode is entered. If the diagnostics menu is entered before transmitting
then these items will indicate NOT TESTED. The 12V and 5V tests are on the switched rails of the IF
receiver. Failure of 5V indicates an IF board problem, the 12V either a MOD/PSU, ribbon cable or IF
Receiver problem, and -5.9V most likely a MOD/PSU or ribbon cable problem. See flowchart for
further diagnosis.
13. SCANNER RESET
When the Radar system is powered up the scanner is in a reset state which the display
acknowledges and then initialises operation. If the power supply to the Radar system is interrupted
(ship’s supply fault) or the scanners’ own PSU goes faulty, it can Reset again. This menu item logs
the number of times that the scanner has reset since power up. During normal operation this should
be zero.
If it is not zero then a fault with the MOD/PSU PCB in the scanner may be the cause, or a Magnetron
failure causing a short circuit on the PSU’s High voltage output and thus causing the PSU to
continually reset. See Flowchart B.
14. SHIP HEADING SENSOR
This test checks the presence of Ships Heading Pulses from the opto PCB in the radome, which
should be once per revolution of the antenna. A FAIL status could either be a failure of the opto PCB,
cable connector etc. Or failure of rotation of the antenna, possibly a Stepper motor problem, belt
drive failure or antenna seizure. See flow chart for further diagnosis. The test is part of a combined
Status Report 1 test and is performed once every 4 sec’s.
15. MAGNETRON HEATER
This test detects the presence of current being drawn by the Magnetron heater during standby and
transmit operation. The detection circuit uses a differential transistor pair (Q62 and Q63 - sheet 3 of
the circuit diagram) on the MOD/PSU PCB to monitor the current. If a FAIL status is indicated the
most likely cause is that the magnetron heater wire(s) are disconnected /damaged/ corroded at
connector CN6 of the MOD/PSU PCB. Alternatively, failure of the PSU units 6.3V heater supply is
suspected. This test is also part of the combined Status Report 1 test and is performed once every
4 sec’s.
Service Manual 83139-1-Ch3 41
Part 2
Chapter 3
10, 11, 12. RECEIVER SUPPLY (12V, -5.9V and 5V)
Pathfinder Radar/Chartplotter Series
16, 17. EEPROM WRITE/READ
If a FAIL status is indicated it means an error has occurred with a read or write operation from the
scanner EEprom within the last 4 seconds (i.e. since the test was last performed, as this test is also
part of the combined Status Report 1 test which is performed once every 4 sec’s). It is unlikely that
an intermittent or occasional error would occur, and as the information is updated at 4 sec intervals
the service engineer is unlikely to enter the menu at the right time to spot such errors.
Therefore if a FAIL is indicated check the following:
Read errors:
Part 2
Chapter 3
•
The majority of the EEprom read operations occur at initial power up. A read failure would mean
that the display would not show correct scanner description information ( size, power, build
standard etc.) and the automatic TUNE function would not work.
Write errors:
•
The display writes to the scanner EEprom when the transmit pulse length is changed (e.g. from
3/4 to 1 1/2 nm and from 3nm to 6nm) to store the current FINE TUNE value for the automatic
tune function . To check operation, switch on the radar and allow to warm up for ten minutes with
the TUNE function in automatic mode (in short pulse 3/4 nm range for example). Now switch to
medium range (1 1/2 nm), the display should take a few rotations to reach optimum TUNE. Now
switch back to short range - the display should be tuned instantly - a delay in tuning could
indicate an EEprom write failure.
•
The other write operations occur when the ADVANCED SET-UP menu items are adjusted and if
the SCANNER SETTINGS hidden menu items are changed. A write failure here would be
indicated if the newly adjusted value is lost when the unit is powered off and on again.
In either case, the scanner IF Receiver PCB should be replaced.
18, 19. FACTORY SETUP / IF TUNED
These tests are performed simultaneously, once only when the system is powered up. They check
that the IF receiver PCB in the scanner has been set up correctly at the factory. These items should
always be PASS unless the EEprom has become corrupted or if by some event an incorrect IF
receiver PCB is fitted. In any case, if either indicate a FAIL then the scanner IF Receiver PCB should
be replaced.
20, 21, 22. MODULATOR CURRENT (SP, MP, LP)
When the Radar is running in transmit mode, the display monitors the modulator current that the
magnetron is drawing for each pulse length that has been used. This value is then displayed next to
the appropriate pulse length ( SP = short pulse, MP = medium pulse, LP = Long pulse). If a
particular pulse length has not been used yet then it indicates NOT TESTED.
If there are no Radar target returns on the display or “poor” radar performance is experienced
referring to these values may indicate if there is a magnetron problem or not.
42 Service Manual 83139-1-Ch3
Chapter 3. Fault Finding
The readings should lie within the ranges given in the table below:
Scanner Power
Pulse Length
PASS Range
2kW
SP
MP
LP
96-153
112-153
112-153
4kW
SP
MP
LP
66-123
81-123
91-123
Figure 19. Modulator current
This item shows the measured rotation time of the scanner. The scanner rotates at a nominal 24
rpm, so the nominal rotation time should be 2,500 milliseconds. This provides another useful
indication that the antenna is indeed rotating correctly inside the radome. A gross error in the timing
would indicate the same problems as for the Ship’s Heading Sensor item.
24. STC PRESET MAX
This item displays the factory set STC curve level. If an STC curve problem is suspected ( e.g.
targets fading as they come closer in range to the vessel) then the “used” STC curve level may be
adjusted from the Advanced Settings Menu. A factory reset should be performed before making any
adjustments to ensure that the scanner is in its correct initial state. Ensure that the scanner is
connected during this operation.
To perform a factory reset: Put the Radar in stand-by mode, press the MENU key. Press the
SYSTEM-SET UP soft key, press and hold MENU for 5 seconds.
Service Manual 83139-1-Ch3 43
Part 2
Chapter 3
23. ROTATION TIME
Part 2
Chapter 3
Pathfinder Radar/Chartplotter Series
44 Service Manual 83139-1-Ch3
Chapter 4. Setting-up Procedures
Chapter 4. Setting-up Procedures
4.1 Fitting of Replacement IF Receiver PCB
If a new IF PCB is fitted to the Radar scanner as the result of a service operation, it will not have the
scanner size and Modulator Power items stored in its EEprom (as the IF receiver is supplied as a
common Spares item for all Pathfinder Radars). In this case the service engineer should set these
by using the following procedure:
Select Scanner Settings Menu by following “hidden” key press:
•
Press MENU
•
Select RADAR SET UP
•
Press and hold CLEAR for approx. 5 secs
•
Select SCANNER SETTINGS soft-key
•
Scroll down the Menu using the trackpad and adjust the Scanner Size and Modulator Power
using the softkeys.
•
For current systems, the RL72/RL72RC is 18" and 2KW, the RL74/RL74RC is 24" and 4KW.
•
Press ENTER to store the values and leave the menu.
•
Check that the maximum selectable Radar range is now 24nm (RL72/RL72RC) and
48nm (RL/RL74/RL74RC).
Part 2
Chapter 4
•
The IF PCB also stores the Bearing Alignment, Display Timing and Tune Preset Data. These items
should be checked and adjusted as necessary. This is described below.
4.2 Fitting of Replacement Magnetron or LNC
If a new Magnetron or LNC is fitted as the result of a service operation, the Tune preset setting may
need to be adjusted.
Important: The Magnetrons fitted to these radars will be either of Toshiba or NJRC manufacturer. If
a magnetron is to be replaced, one of the same type and same manufacturer must be selected.
4.3 Bearing Alignment
The bearing alignment is normally set when you first install your system, and is described in
Section 6.9, Bearing Alignment, of the Owner's Handbook. It should be checked periodically.
The bearing alignment corrects for display azimuth error. It can be set to a value in the range -180° to
+180°, in increments of 0.5°.
4.4 Display Timing
If you extended the inter-unit cable, you should have set the display timing when you first installed
your system, as described in Section 6.9, Display Timing Adjustment of the Owner's Handbook. This
will need to be repeated (for extended inter-unit cables) if the Scanner Reset has been carried out.
If you wish to turn off Main Bang Suppression when adjusting the display timing, press the MBS soft
key to toggle the setting. MBS is reset to ON automatically when you finish adjusting the display timing.
Service Manual 83139-1-Ch4 45
Pathfinder Radar/Chartplotter Series
4.5 Tune Preset
Part 2
Chapter 4
If the IF receiver PCB, LNC assembly, or the Magnetron has been replaced, then the Tune Preset
should be checked and adjusted if necessary as described in Section 5.5, Tune Preset of the
Owner's Handbook.
46 Service Manual 83139-1-Ch4
Chapter 5. Replacement Parts
Chapter 5 . Replacement Parts
This chapter contains the Spare Parts Lists for the 18'' and 24'' radar scanner units. This is followed
by a number of notes on how to obtain access to specific parts and how to replace them. Generally
identification of parts and their replacement can be caried out by referring to the exploded view
drawings at the rear of this chapter.
5.1 Spare Parts Lists
18'' Radar Scanner Unit
The Item numbers refer to Figure 20: 18'' and 24'' Scanner Unit.
Item
Spare Description
Part No.
Comment
Top cover ‘Raytheon’, including:
18'' Radome top
Square shoulder nut (x4)
Radome label set
W101
Not illustrated
1
Base. including:
18'' Radome Base
Cable clamp
Screw, M4 x 16 (x2)
Cable gland
Nylon lock nut
Cable gland washer
Rating label
W103
2
Case Seal
R085
3
Antenna & Rotary Joint, including:
Rotary joint sub-assembly
Protection cap
R086
24'' Radar Scanner Unit
When ordering spares, quote the Spare Description, prefixed by 24'' Radar and the Part No.
The Item numbers refer to Figure 20: 18'' and 24'' Scanner Unit.
Item
Spare Description
Part No.
Comment
Top Cover ‘Raytheon’, including:
24'' Radome top
Square shoulder nut (x4)
Radome label set
W105
Not illustrated
1
Base, including:
24'' Radome base
Cable clamp
Screw, M4 x 16 (x2)
Cable gland
Nylon lock nut
Cable gland washer
Rating label
W107
2
Case Seal
R087
3
Antenna & Rotary Joint, including:
Rotary joint sub-assembly
Protection cap
R088
Service Manual 83139-1-Ch5 47
Part 2
Chapter 5
When ordering spares, quote the Spare Description, prefixed by 18'' Radar and the Part No.
Pathfinder Radar/Chartplotter Series
Radar Core Assembly
When ordering spares, quote Spare Description (prefixed by Radar for items 4 to 16 ) and the Part No.
The Item numbers refer to Figures 20 and 21: 18'' and 24'' Scanner Unit.
Item
Spare Description
Part No.
Core Seals, including:
Core Seal
‘O’ Ring (x4)
Foot seal (x4)
R089
5.1
5.2
5.3
Magnetron 2kW Toshiba, including:
Magnetron 2kW
Rubber boot
Connector housing
Terminal (x2)
Sleeve, 175mm
Cable screen
R090
Magnetron 2kW NJRC including:
Magnetron 2kW
Rubber boot
Connector housing
Terminal (x2)
Sleeve, 175mm
Cable screen
R58006
Magnetron 4kW Assy, including:
Magnetron 4kW
Rubber boot
Connector housing
Terminal (x2)
Sleeve, 175mm
Cable screen
R091
7
Circulator
R094
8
Stepper motor, including;
Stepper Motor
Terminal (x6)
Connector housing
Drive pulley
Sleeving, 180mm
R095
9
Drive belt
R096
10
Opto PCB assembly, including:
Opto PCB & cable assembly
Cable tie
R104
11
LNC PCB Assy, including:
Receiver LNC PCB
Receiver RAM
LNC screen lid
Conductive washer
R101
12
LNC Connector assembly
R105
13
Modulator PCB 2KW Toshiba
R097
13
Modulator PCB 2KW NJRC
R58007
13
Modulator PCB 4kW
R098
14
IF PCB
R102
IF PCB and support control
15
Core ribbon cable
R103
18 way (modulator to IF)
16
IF Cover, including:
IF Cover and Urethane Tape, 30mm
R108
Part 2
Chapter 5
6.1
6.2
6.1
6.2
6.1
6.2
48 Service Manual 83139-1-Ch5
Comment
Also item 19
Moulded connector assembly (to IF)
Chapter 5. Replacement Parts
17
Receiver cover and seal, including:
Receiver cover
Receiver cover seal
Receiver RAM
R106
LNC
18
Lower cover and insulator, including:
Lower cover and Insulator
High voltage label
R107
Modulator
18" and 24'' Scanner (common spares)
Item
19
Spare Description
Part No.
Comment
18'' & 24'' Drain tube
R123
Not illustrated
18'' & 24'' Foot seal (x4)
R124
Also part of item 5
18'' & 24'' Lanyard, comprising:
Polypropylene lanyard, 500mm
R125
Not illustrated
18'' & 24'' Radar fittings pack, including:
Bolt - M8 x 40mm (x4)
Washer, spring - M8 (x4)
Washer - M8 (x4)
W104
Not illustrated
Radome fixing screw kit, including:
Case screws (x4)
‘O’ Ring, 3/16 inch ID (x8)
Washer - M4 (x4)
D346
Not illustrated
Radar cable connector kit
R126
Not illustrated
Bitumen washer (x4)
R141
Not illustrated
4.2 18'' and 24'' Scanner Units - replacement of parts
The following notes supplement the exploded view drawings to assist with access to, or
replacement of Parts.
WARNING:The scanner unit contains high voltages. Before removing the cover switch off
the radar and isolate the power source.
Refer to the scanner units Spare Parts List and the exploded view drawings. Figures 20 and 21.
Replacement of scanner unit parts fall into two categories:
Category A. Can be accessed with the scanner installed.
1.
Top cover
2.
Case Seal
3.
Antenna & Rotary Joint
4.
Magnetron 2kW, or 4kW
5.
Circulator
6.
Drive Belt
7.
LNC PCB Assembly
8.
Drain Tube
9.
Lanyard
10. Radar Cable Connector
11. Receiver Cover and Seal
Service Manual 83139-1-Ch5 49
Part 2
Chapter 5
When ordering spares, quote the Spare Description and the Part No.
The Item 19 refers to Figure 20: 18'' and 24'' Scanner Unit.
Pathfinder Radar/Chartplotter Series
Part 2
Chapter 5
Category B. Requires the removal of the scanner, so that the Core can be separated from the
Radome Base.
1.
Radome Base
2.
Core 18'' & 24''
3.
Stepper Motor *
4.
Opto PCB Assembly *
5.
LNC Connector Assembly *
6.
Modulator PCB 2kW, or 4kW *
7.
IF PCB
8.
Core Ribbon Cable
9.
IF Cover
10. Lower Cover and Insulator
*Removal of these items requires actions both inside and outside the core.
Note: Fitting and seal kits have been omitted from the above lists.
Category A
1. Top Cover. When refitting the top cover do not over tighten the 4 securing screws
(6 lb.in, or 0.7 Nm).
2. Case Seal. Always check the condition of the case seal and replace if necessary, before fitting
the top cover.
3. Antenna & Rotary Joint.
WARNING:The Antenna must not be separated from the Rotary Joint. Do not unsolder the
antenna probe, or release any of the antenna fixings.
Remove the complete assembly by first releasing the drive belt from the motor pulley wheel. Then
remove the 4 screws (item 20) accessed through the holes in the top of the locking ring (which
supports the plastic pulley wheel) and lift the complete assembly clear of the core.
Take care not to damage the probe protruding below the rotating joint. The bearings must not be
packed with additional grease.
When fitting the antenna & rotating joint, position the drive belt above the plastic pulley wheel, align
the flat on the bearing retaining plate with the flat on the core casting and then rotate the locking ring
so that the 4 screws can be refitted. Make certain the drive belt is free from dirt or grease and refit to
the pulley wheels.
4. Circulator.
WARNING:The Circulator must not be taken apart.
To remove the circulator slacken the 4 lower screws and remove the 4 upper screws.
When fitting the circulator replace all the screws loosely and then tighten evenly.
5. Drive Belt. The Antenna & Rotating Joint must be removed if the drive belt is to be replaced.
Ensure the drive belt is free from grease and dirt before fitting.
6. LNC PCB Assembly. It is recommended that the antenna & rotary joint is removed (see 3. above)
to gain access to the receiver cover screws.
When refitting the LNC PCB assembly take care not to damage the RF probe and ensure that
50 Service Manual 83139-1-Ch5
Chapter 5. Replacement Parts
the conductive washer is in place on the probe. Do not over tighten the 5 securing screws
(6 lb.in, or 0.7 Nm).
A new LNC PCB will require the Advanced Settings to be checked and adjusted, if necessary, as
detailed in the Owner's Handbook in section 5.5 and 6.9.
7. Drain Tube. Fitting of the drain tube is described in the Owner's Handbook, section 6.6,
Connecting the Scanner.
Category B
8. Core 18'' and 24''
Replacement of any category ‘B’ item will necessitate the removal of the core from the radome base.
Generally the scanner unit should be removed from its mounting to a safe location by disconnecting
and removing the inter-unit cable and releasing the 4 M8 bolts. Protect the end of the inter-unit
cable.
The core is then removed by releasing the 4 small securing screws (item 24).
9. Stepper Motor. To disconnect the motor cable remove the lower cover and insulator (see 13.
below) and the modulator PCB.
10. Opto PCB Assembly. It is recommended that the antenna and rotary joint is first removed
(see 3. on page 50) to obtain access to the opto PCB. To disconnect the opto PCB cable remove
the lower cover and insulator (see 13. below) and the modulator PCB.
11. LNC Connector. First remove the antenna & rotary joint (see 3. on page 50), the receiver cover
and seal and the LNC PCB assembly (see 6. on page 50). Next remove the lower cover and
insulator (see 13. below), modulator PCB, IF cover and IF PCB.
12. IF PCB. If a new IF PCB is fitted, then the Bearing Alignment and Advanced Settings should be
checked and adjusted as necessary as detailed in the Owner's Handbook section 5.5 and 6.9.
13. Lower Cover and Insulator. When refitting the lower cover to the core ensure that the insulated
section is placed over the high voltage part of the modulator PCB.
Service Manual 83139-1-Ch5 51
Part 2
Chapter 5
WARNING: When working on the underside of the core, ensure the antenna is protected
from physical damage.
Pathfinder Radar/Chartplotter Series
1.
2.
3.
5.1
5.2
5.3
23(x5) 20(x4)
Base
Case seal
Antenna and rotary joint
Core seal
'O' ring (x4)
Foot seal (x4)
6.1
6.2
7.
8.
9.
10.
11.
12.
17.
20.
21.
22.
23.
24.
25.
26.
17
20(x4)
Part 2
Chapter 5
3
Magnetron (2kW/4kW)
Rubber boot
Circulator
Stepper motor
Drive belt
Opto PCB assembly
LNC PCB assembly
LNC connector assembly
Receiver cover and seal
Screw - M3, 8mm (x8)
Screw - M4, 8mm (x15)
Washer (x6)
Screw - M3, 16mm (x5)
Screw - M4, 16mm (x4)
Washer, spring (x4)
Screw - M3, 12mm (x1)
6.1
9
11
8
21
22 21(x4)
22
21(x2)
7
21(x8)
6.2
26
(x1)
10
12
24(x4)
25(x4)
Figure 20. 18'' & 24'' scanner
52 Service Manual 83139-1-Ch5
22(x4)
5.2
5.3 5.1
or 19
2
1
D3857-1
Chapter 5. Replacement Parts
20 (x4)
18
20 (x7)
Part 2
Chapter 5
26 (x2)
13
15
20 (x7)
16
20 (x5)
14
8.
12.
13.
14.
15.
16.
18.
20.
26.
12
Stepper motor
LNC connector assembly
Modulator (2kW/4kW)
IF PCB
Core ribbon cable
IF cover
Lower cover and insulator
Screw - M3, 8mm (x23)
Screw - M3, 12mm (x2)
8
D3858-1
Figure 21. 18'' & 24'' scanner
Service Manual 83139-1-Ch5 53
Part 2
Chapter 5
Pathfinder Radar/Chartplotter Series
54 Service Manual 83139-1-Ch5
Chapter 6. Drawings
Chapter 6. Drawings
List of drawings
Part 2
Chapter 6
18" (2kW) and 24" (4kW) Scanner Interconnections ....................................... 56
Modulator/PSU Board – Top level .................................................................. 57
Modulator/PSU Board – Low Voltage PSU ..................................................... 58
Modulator/PSU Board – High Voltage PSU .................................................... 59
Modulator/PSU Board – Modulator ................................................................ 60
Modulator/PSU Board – 3 Phase DC brushless motor drive ............................ 61
Modulator/PSU Board – Stepper Motor Drive ................................................. 62
Modulator/PSU Board – PCB layout (2kW, stepper motor) .............................. 63
Modulator/PSU Board – PCB layout (4kW, stepper motor) .............................. 64
IF Receiver – Top level ................................................................................. 65
IF Receiver – PCB Layout ............................................................................. 66
Service Manual 83139-1-Ch6 55
Pathfinder Radar/Chartplotter Series
Part 2
Chapter 6
18" (2kW) and 24" (4kW) Scanner Interconnections
TITLE
18"(2KW) and 24"(4KW) SCANNER INTERCONNECTIONS
D3853-2
56 Service Manual 83139-1-Ch6
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ISSUE
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A
Chapter 6. Drawings
Part 2
Chapter 6
Modulator/PSU Board – Top level
TITLE
MODULATOR/PSU BOARD -- TOP LEVEL
D3861-3
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Service Manual 83139-1-Ch6 57
Pathfinder Radar/Chartplotter Series
Part 2
Chapter 6
Modulator/PSU Board – Low Voltage PSU
TITLE
MODULATOR/PSU BOARD - LOW VOLTAGE PSU
D3863-3
58 Service Manual 83139-1-Ch6
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Chapter 6. Drawings
Part 2
Chapter 6
Modulator/PSU Board – High Voltage PSU
TITLE
MODULATOR/PSU BOARD - HIGH VOLTAGE PSU
D3862-3
DERIVED FROM DRAWING No.
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Service Manual 83139-1-Ch6 59
Pathfinder Radar/Chartplotter Series
Part 2
Chapter 6
Modulator/PSU Board – Modulator
TITLE
MODULATOR/PSU BOARD - MODULATOR
D3860-3
60 Service Manual 83139-1-Ch6
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Chapter 6. Drawings
Part 2
Chapter 6
Modulator/PSU Board - 3 Phase DC brushless motor drive
Not applicable to
Radome Scanner Radars
TITLE
MODULATOR/PSU BOARD - 3 PHASE DC BRUSHLESS MOTOR DRIVE
D3909-3
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Service Manual 83139-1-Ch6 61
Pathfinder Radar/Chartplotter Series
Part 2
Chapter 6
Modulator/PSU Board – Stepper Motor Drive
TITLE
MODULATOR/PSU BOARD – STEPPER MOTOR DRIVE
D3864-3
62 Service Manual 83139-1-Ch6
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Chapter 6. Drawings
Part 2
Chapter 6
Modulator/PSU Board – PCB layout (2kW, stepper motor)
TITLE
MODULATOR/PSU BOARD PCB LAYOUT (2kW, STEPPER MOTOR)
D4098-3
DERIVED FROM DRAWING No.
ISSUE
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Service Manual 83139-1-Ch6 63
Pathfinder Radar/Chartplotter Series
Part 2
Chapter 6
Modulator/PSU Board – PCB layout (4kW, stepper motor)
TITLE
MODULATOR/PSU BOARD PCB LAYOUT (4kW, STEPPER MOTOR)
D4096-3
64 Service Manual 83139-1-Ch6
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ISSUE
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S
1 of 2
Chapter 6. Drawings
Part 2
Chapter 6
IF Receiver – Top level
TITLE
IF RECEIVER - TOP LEVEL
D3865-3
DERIVED FROM DRAWING No.
ISSUE
SHEET
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F
1 of 6
Service Manual 83139-1-Ch6 65
Pathfinder Radar/Chartplotter Series
Part 2
Chapter 6
IF Receiver – PCB Layout
TITLE
IF RECEIVER - PCB LAYOUT
D4097-3
66 Service Manual 83139-1-Ch6
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ISSUE
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1 of 1
Pathfinder Radar/Chartplotter Series
Service Manual 83139
Pathfinder Radar/Chartplotter Series
Document Number: 83139
October 1998
Printed in England
Raytheon Marine Company
676 Island Pond Road
Manchester
New Hampshire 03109-5420
Tel: (001 603) 647 7530
Fax: (001 603) 634 4756
Service Manual 83139
Raytheon Marine Company
Anchorage Park, Portsmouth
Hampshire PO3 5TD
Tel: (01705) 693611
Fax: (01705) 694642
http: //www.raytheon.com